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Agradecimentos: We thank Dr. Dario Campana, St Jude Children’s Research Hospital for kindly providing the hTERT + bone marrow mesenchymal cell line. We also acknowledge Prof. Dr. Antonio Riul Junior and Dr. Mawin Javier Martinez Jimenez from DFA-IFGW, UNICAMP, for their support in the electrochemical tests. This work was supported by the São Paulo Research Foundation (FAPESP), grants #2019/18460-4, #2019/04943-3 and #2018/24461-0 and FAPERGS, grant #19/2551-0002288-3. FC and LLA are FAPESP fellows. VP is CAPES fellow (grant #88887.475264/2020-00). JAY, CAF and FA are CNPq fellows Abstract: This study combines the brand new concept of high-entropy designed materials with the superior properties of metallic glasses to obtain a NbTaTiVZr high-entropy metallic glass (HEMG) coating for biomedical applications. The amorphous structure is achieved by a room temperature magnetron sputtering deposition, whereas a bcc crystalline phase, typical of high-entropy alloys (HEA), is obtained at 400 degrees C. X-ray photoelectron spectroscopy showed that the oxygen concentration on the coatings surface is > 50% and significantly higher than in the bulk (similar to 5%). The NbTaTiVZr(O) HEMG surface is completely passivated, in contrast to the metallic + oxide outermost layer found for the HEA. Potentiodynamic polarization tests attested an improved corrosion resistance of the HEMG surface, which showed also increased hydrophilicity compared to the crystalline sample. In vitro biocompatibility investigations using both the hTERT-immortalized bone marrow mesenchymal cells and MG-63 osteosarcoma cells showed excellent viability (similar to 98% and similar to 96%, respectively) and adhesion onto the HEMG coating after 96 h of incubation, indicating the integrity and biosafety of this surface. The cell viability and proliferation on the HEA and Ti (used as a benchmark) surfaces were much inferior. The enhanced surface protection and the superior biocompatibility makes the HEMG promising to be employed as a biocoating on orthopedic implants FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) under Project Nos. 14/23399-9, 18/08543-7, and 2021/06893-3. I.D.B. acknowledges the financial support from the Brazilian Nanocarbon Institute of Science and Technology (INCT/Nanocarbono) and Brazilian Synchrotron Light Laboratory (LNLS) Abstract: We present the design, implementation, and illustrative results of a light collection/injection strategy based on an off-axis parabolic mirror collector for a low-temperature Scanning Tunneling Microscope (STM). This device allows us to perform STM induced Light Emission (STM-LE) and Cathodoluminescence (STM-CL) experiments and in situ Photoluminescence (PL) and Raman spectroscopy as complementary techniques. Considering the etendue conservation and using an off-axis parabolic mirror, it is possible to design a light collection and injection system that displays 72% of collection efficiency (considering the hemisphere above the sample surface) while maintaining high spectral resolution and minimizing signal loss. The performance of the STM is tested by atomically resolved images and scanning tunneling spectroscopy results on standard sample surfaces. The capabilities of our system are demonstrated by performing STM-LE on metallic surfaces and two-dimensional semiconducting samples, observing both plasmonic and excitonic emissions. In addition, we carried out in situ PL measurements on semiconducting monolayers and quantum dots and in situ Raman on graphite and hexagonal boron nitride (h-BN) samples. Additionally, STM-CL and PL were obtained on monolayer h-BN gathering luminescence spectra that are typically associated with intragap states related to carbon defects. The results show that the flexible and efficient light injection and collection device based on an off-axis parabolic mirror is a powerful tool to study several types of nanostructures with multiple spectroscopic techniques in correlation with their morphology at the atomic scale and electronic structure FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: This work was financially supported by the Brazilian agencies CNPq and FAPESP-FAPERGS (Grant 2019/18460–4). ARZ and FA are CNPq fellows (Grants 303233/2017–6 & 302370/2015–3). FGE and FC are FAPESP fellows (Grants 2019/00757–0 & 2018/24461–0) Abstract: To a large extent, future technological progress relies on the study-development of advanced materials with new and/or improved properties. The semiconductors titanium oxynitride (TixOyNz) and titanium dioxide (TiO2) perfectly meet these requirements in the sense that their main chemical and structural properties can be customized, leading to successful contributions in optics, electronics, catalysis, bactericides surfaces, and photovoltaics applications, for instance. Motivated by these aspects, this paper reports on the structure and optical bandgap of TixOyNz, as obtained by Raman scattering and optical transmittance spectroscopy, respectively. The study comprises a set of films produced by N-2-plasma Ti sputtering and subsequently thermal annealed in an atmosphere of oxygen flux. As the thermal treatments advance, the Raman spectra indicate a gradual transformation of the films from amorphous+(nano/micro-)crystalline TixOyNz to the crystalline Rutile phase of TiO2 (R-TiO2). Consistent with these structural changes, the optical bandgap of the films decreases from - 3.2 to 2.5 eV, i.e., across part of the ultraviolet-blue spectral region. The analysis of the experimental data confirms the importance of nitrogen (in the early stages of sample preparation) on the achievement of R-TiO2 in a continuous and controllable way. Therefore, this paper shows the suitability of the TixOyNz compound to produce films with well-defined crystalline TiO2-related structures and specific optical bandgap values CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS Fechado

Agradecimentos: This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001 with PROSUC/CAPES scholarships (L. M. L., D. M. and G. L. R), by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) - grants 304831/2014-0 and 305253/2018-2 (CAP), 304675/2015-6 and 305528/2018-1 (JEZ), 302370/2015-3 (FA) and 308567/2018-8 (CAF), Programa de Apoio a Núcleos de Excelência (PRONEX), Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS) - Project 2019/18460-4 - FAPESP-FAPERGS. This research was also made possible thanks to computational resources provided by the Centro de de Computação Científica (NCC/GridUNESP), Universidade Estadual de São Paulo (UNESP), Núcleo Avançado de Computação de Alto Desempenho (NACAD) da COPPE, Universidade Federal do Rio de Janeiro (UFRJ), and Centro Nacional de Supercomputação, Universidade Federal do Rio Grande do Sul (CESUP/UFRGS) Abstract: Friction behavior at the nanoscale may be split into different contributions, including phononic dissipation. Despite the isotopic effect in the phononic component being previously explored, experimental and theoretical approaches determined contradictory conclusions. Here, a desorption-based model is proposed, and it is found to be consistent with previously published experimental data on hydrogenated and/or deuterated amorphous carbon films. Moreover, molecular dynamics simulations showed that a surface coverage difference as low as 5% might promote an effect on friction even greater than that observed experimentally. This happens when reactive defects are created after desorption (prompting carbon dangling bonds), reinforcing the assumption that minor surface differences may be sufficient for the effects observed, meeting both experimental and theoretical approaches in the same overall trend. Therefore, the phononic dissipation occurs, but the isotopic effect may be indirect, where the desorption rate of hydrogen and deuterium plays a role by exposing carbon dangling bonds, changing the interface of interaction and the nanoscale friction ultimately COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: The authors would like to thank SERB [grant number: EMR/2017/001196] to support this research. The authors acknowledge NIMS, Japan TEM station, and SAIF facility at IIT Bombay for supporting TEM studies. The cooperation of Ms. Letícia T. Bim (UCS, Brazil) and Dr. Vinod Kumar’s research team (IITI) is acknowledged for GDOES and TGA experiments, respectively. DO also acknowledges Swedish Research Council (Vetenskapsrådet) for a financial support through a research grant # 2016-03811 Abstract: The present study investigates the high-temperature oxidation behaviour of nanostructure surface layered AISI 304L stainless steel. A severely deformed layer of -300 mu m thickness, consisting of nanoscale grains (-40 nm size) in the topmost region, is successfully developed using the surface mechanical attrition treatment (SMAT) process. The SMATed layer is substantially stable up to 700 degrees C; however, the surface hardness is reduced by -37% at 800 degrees C for 25 h oxidation duration. Glow discharge optical emission spectroscopy and X-ray photoelectron spectroscopy analysis revealed the considerable difference in the chemistry and elemental distribution across the oxide scale of SMATed and non-SMATed specimens. Adherent, denser, and thinner scale, dominated by nanocrystals of Cr- and Mn-rich oxides, is formed on the SMATed steel. However, the Fe-oxide dominated scale containing micro-crystals is found on the non-SMATed specimens, which shows noticeable exfoliation. A high density of grain boundaries and lattice defects in the SMATed layer display admirable reactive diffusion properties of Cr and Mn during oxidation of steel, instigating the formation of a protective oxide scale. The SMATed specimens exhibit multiple zones in the oxide scale: (i) Cr/Mn depleted outer layer, (ii) Cr-/Mn-rich inner layer, and (iii) gradually decreasing Cr/Mn region Fechado

Agradecimentos: Part of this work was supported by FAPESP Project Nos. 2012/10127-5, 2019/24095, 2019/18460-4, 2019/00757-0, 2018/24461-0. C.A.F. and F.A. are CNPq’s fellows. This paper is part of the Ph.D. thesis of VGA realized in the IFGW, UNICAMP, Brazil. The authors are grateful to C. Piacenti for technical help Abstract: This paper reports the competition of H2O (residual) and H-2 by site (defects) on the Si surface, created by Xe+ ion bombardment. X-ray photoelectron spectroscopy (XPS) in an ultrahigh vacuum system attached to the sample preparation chamber provided the data for the analyses. As hydrogen cannot be detected by XPS, an indirect method to evaluate the O and H cover ratio was developed. The hydrogen passivation effect obtained by the formation of the Si-H bond due to H-2 chemisorption limits Si-OH and Si-O-Si bonds, which are products of H2O dissociation. In addition, the results have shown that Xe+ ion bombardment diminished the H-2 chemisorption energy barrier onto Si FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: The authors are grateful to UCS, CAPES to PROSUC (#88887.153304/2017-00) and PDSE (#88881.362240/2019-01) for financial support to C.D.B. and CNPq (#422372/2016-1), FAPERGS (#19/2551-0002288-3), FAPESP (#2019/18460-4), and Plasmar Tecnologia Ltda. (#1408-25.51/14-6) for financial support. C.D.B., L.M.L., A.F.M., J.S.W., and C.A.F are CNPq or CAPES fellows. F.C. is an FAPESP fellow (project #2018/24461-0). The authors R.S., M.E., F.F., and A. C. would also like to thank funding from CEMMPRE UIDB/00285/2020 [co-financed via FEDER and FCT] and the IFGW-UNICAMP and Epipolé Research Group for their willingness to help with this research Abstract: The low adhesion of amorphous carbon (a-C) films on ferrous alloys has restricted massive industrial application since their development, restricting application to mechanical and electromechanical components. Although different mechanisms have been raised to describe the a-C film adhesion, the chemical affinity and the role of oxygen at the interfaces are the key issue. Nevertheless, a quantitative approach considering the oxygen adsorption and the adhesion strength/base pressure relationship is still not proposed, which would be of special interest in industry. In this study, we analyze the influence of the base pressure on the adhesion of amorphous carbon (a-C) films onto a ferrous alloy intermediated by a nanometric silicon interlayer. The different base pressure deposition resulted in different adhesion of the films. By means of structural and chemical techniques, the oxygen content at the interfaces was quantified and correlated with the base pressure before thin film deposition. We propose a quantitative physicochemical model that correlates the a-C film adhesion with oxygen located at the interfaces, which is indirect evidence of its previous presence in the deposition chamber, as a fraction of the residual gases from the base pressure. As adhesion depends on oxygen content, we used the Langmuir isothermal law to evaluate this dependence with good agreement. This model may be of potential interest in plasma surface engineering and process automatization not only for carbon-related materials deposited on metals, mainly in its potential use as a solid lubricant COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: This work was financially supported by the Brazilian agencies CNPq and FAPESP (Project 2019/18460-4). ARZ and FA are CNPq fellows (Grants 303233/2017-6 & 302370/2015-3). FC and FGE are FAPESP fellows (Grants 2018/24461-0 & 2019/00757-0) Abstract: Owing to its singular and (to some extend) adaptable characteristics, titanium oxynitride (TixOyNz) represents an exceptional choice in the realm of new materials aiming at the development of practical devices. However, the effective use of TixOyNz in photovoltaic and (photo)catalysis applications, for example, relies on a refined production-properties balance. Accordingly, this paper reports on the physico-chemical properties of TixOyNz films as investigated by means of the Raman scattering and X-ray photoelectron spectroscopy (XPS) techniques - the former shedding light on the structural characteristics of the films, and the latter providing the state of oxidation of the film's constituents. The films were prepared by sputtering TiO2 and Ti targets in a plasma comprising different mixtures of Ar and N-2. Because of the deposition method and conditions, the films exhibit Raman spectra that are consistent with a combination of TiO2 and TiN or, more properly, TixOyNz under the amorphous and (nano/micro-)crystalline structures. In fact, the experimental data indicate the presence of four TiO2- and two TiN-related phonon modes, whose relative scattering features scale with the oxygen and nitrogen contents of the films. A similar concentration dependence was verified with the percentage of Ti4+, Ti3+, and Ti2+ chemical states of oxidation. This mutual concentration dependence was explored thoroughly and the results clearly indicate the suitability of the Raman data to estimate the typical atom composition and distribution of the Ti-related chemical states of TixOyNz CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: This work was supported by the São Paulo Research Foundation (FAPESP), grants #2019/18460-4 and #2018/24461-0, and FAPERGS, grant #19/2551-0002288-3. FC is FAPESP fellow. SRSM is CAPES fellow. CAF and FA are CNPq fellow Abstract: Metallic sputtered high-entropy alloy (HEA) thin films often result in amorphous structures, due to the film growth kinetics and the large atomic size mismatch of the constituent elements. In this paper, single-phase crystalline NbTaTiVZr HEA thin films were achieved by the appropriate choice of both the alloying elements and the synthesis conditions. Regarding the latter, substrate biasing prompts Ar+ ion irradiation during film growth, whereas substrate heating increases the adatom mobility, inducing specific structural modifications. The control of both variables eliminates traditional crystallization strategies, such as adding nitrogen to the gas mixture during film growth or post-thermal annealing of the as-deposited films. Therefore, we have investigated the relationship between the synthesis conditions, the structure, and the mechanical properties of a Nb20Ta26-Ti22V16Zr16 HEA thin film, due to its potential application in the field of refractory coating materials. The asdeposited films prepared at 400 degrees C possessed a body-centered cubic (bcc) phase, and their preferential orientation changed according to the bias voltage value (V-b) chosen. Low energy ion irradiation (V-b approximate to -25 V) resulted in crystallite coarsening and surface roughening. On the other hand, higher negative bias voltages (V-b approximate to -75 V) led to lower growth rates, grain refining, and improved mechanical properties. In addition, the chemical states and composition were determined by X-ray photoelectron spectroscopy (XPS) and the HEA phase formation was predicted using empirical parameters and compared to the results obtained by the Calculation of Phase Diagrams (CALPHAD) approach FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: This research was financially supported by the Research Support Foundation of the State of São Paulo (FAPESP) and the Brazilian National Council of Scientific and Technological Development (CNPq). F.G.E is a FAPESP fellow (project/grant number 2019/00757-0). A.R.Z. and F.A. are CNPq fellows. Part of this work was supported by FAPESP (projects 2019/24095-7 and 2019/18460-4) Abstract: Optical properties of hydrogenated TiO2 thin films deposited by the ion beam sputtering method are reported. By reducing the oxide by hydrogenation in situ (during deposition) and ex situ (by means of posterior thermal annealing) a controlled phase modification allows to manipulate optical properties to improve photoactivity for solar energy conversion and catalytic applications. The hydrogenation procedure prompts remarkable structural changes and optical properties of the TiO2 hierarchical thin films. Photoemission electron spectroscopy (XPS) results show the presence of titanium in Ti4+ into Ti3+ state of oxidation, i.e., compatible with oxygen vacancies and titanium interstitials. Vibrational properties inspected by IR absorption and Raman spectroscopy allowed identifying potentially catalytic sites and vibration modes associated with hydrogen. The vibrational spectra show that both in situ and ex situ hydrogenation routes contribute to prompt (dis)order in the films, involving the presence of anatase crystalline phase embedded in an amorphous matrix or mixed-phase (anatase rutile) crystalline TiO2. To avoid debate about the TiO2 theoretical (indirect) and expected and measured (direct, normally reported) optical gap (E-gap), the absorption coefficient spectra were analyzed by a recently developed method based on the Boltzmann sigmoidal function. From these analyses, conclusions about defects states prompted by the hydrogenation processes are presented FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: L. M. L., M. E. H. M. C., N. S. F., A. F. M., F. A., and C. A. F. are CNPq or CAPES fellows. The authors would like to thank Epipolé Research Group colleagues for support during this research. This work was financially possible due to the following projects: INCT-INES (CNPq #465423/2014-0), UNIVERSAL 2016 (CNPq #422372/2016-1), and PqG 2017 (FAPERGS #17/2551-0001052-3). Part of this work was supported by FAPESP with grants 2019/24095-7 and 2019/18460-4 Abstract: Friction is a ubiquitous manifestation of nature, and when it is studied at the nanoscale, complex and interesting effects arise from fundamental physical and chemical surface properties. Surprisingly, and probably due to the complexity of nanofriction studies, this aspect has not been completely discussed in prior studies. To fully consider the physicochemical influence in nanoscale friction, amorphous carbon films with different amounts of hydrogen and fluorine were prepared, chemically characterized, and evaluated via lateral force microscopy. Hydrogen and fluorine were selected because although they exhibit different physicochemical properties, both contribute to frictional force reduction. Indeed, to explain the experimental behavior, it is necessary to propose a new damping constant unifying both polarizability (physical) and electronegativity (chemical) properties. The satisfactory agreement between theory and experiments may encourage and enhance deeper discussion and new experiments that take into account the chemical peculiarities of frictional behavior relating to nanoscale elastic regimes CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors are grateful for the financial support of the Ministry of Science, Technology, and Innovation of Colombia (Minciencias) and the Colombian Society of Physical Engineering (SCIF), and the Fundación de Amparo à Pesquisa do Estado de São Paulo (FAPESP, grants # 2012/1027-5, 2019/18460-4). The authors thank the IEEE 2020 global humanitarian engineering project "Community technology literacy through 3D printing technology and energy harvesting cells for water monitoring applications". F.A. and A.R. are CNPq fellows. M.J.M.J. is a fellow of Minciencias. The authors are also grateful to Prof. Elidiane Cipriano Rangel from the Laboratory of Technological Plasmas (UNESP, Sorocaba, SP, Brazil) for the first SEM analyses. The authors wish to thank LABNANO, Centro Brasileiro de Pesquisas Físicas-RJ, Brazil, for the SEM measurements Abstract: Heavy metal pollution is posing a severe health risk on living organisms. Therefore, significant research efforts are focused on their detection. Here, we developed a sensing platform sensor for the selective detection of lead(II) acetate. The sensor is based on self-assembled polyethyleneimine-functionalized carbon nanotubes (PEI-CNTs) and graphene oxide films deposited onto gold interdigitated electrodes. The graphene-based nanostructure showed a resistive behavior, and the fabricated layer-by-layer film was used to detect Pb(II) acetate in an aqueous solution by comparison of three electrochemical methods: impedance spectroscopy, amperometry, and potentiometry stripping analysis. The results obtained from different methods show that the detection limit was down to 36 pmol/L and the sensitivity up to 4.3 µAL/µmol, with excellent repeatability. The detection mechanism was associated with the high affinity of heavy metal ions with the functional groups present in the PEI-CNTs and GO, allowing high performance and sensitivity. The achieved results are important for the research toward integrated monitoring and sensing platforms for Pb(II) contamination in drinking water FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: The authors would like to thank Ms. Letícia T. Bim (UCS, Brazil) and Dr. Vinod Kumar’s research-team (IITI) for the cooperation in GDOES and TGA experiments, respectively. Authors acknowledge Raman Spectrometer facility (supported by DST-FIST (grant number SR/FST/PSI-225/2016)) at Dept. of Physics, IITI. The Nanoindentor facility of IIT Bombay is also kindly acknowledged. GDOES measurements were partially supported by the Grant CNPq-INCT-INES # 465423/2014-0. XPS analysis was supported by the projects from FAPESP 2012/10127-5; 2018/24461-0; 2019/24095; 2019/18460; 2019/00757-0. CAF, FA, and VA are the CNPq fellows. Authors acknowledge Raman Spectrometer facility (supported by DST-FIST (grant number SR/FST/PSI-225/2016)) at Department of Physics, IITI. The Nanoindentor facility of IIT Bombay is also kindly acknowledged. GDOES measurements were partially supported by the Grant CNPq -INCT-INES # 465423/2014-0. XPS analysis was supported by the projects from FAPESP 2012/10127-5; 2018/24461-0; 2019/24095; 2019/18460; 2019/00757-0. CAF, FA, and VA are the CNPq fellows Abstract: The present study deals with the properties of boronized and non-boronized low-alloy steel (34CrAlMo5-10). Specimens are characterised using microscopy, various spectroscopic techniques, nanoindentation, surface profilometer, and tribometer. The boronized region contains (i) (Fe, M)(2)B columns and (ii) matrix between the columns. Nanoindentation study reveals the difference in the mechanical behaviour of boride, matrix, and core regions. Strain-rate sensitivity of different regions of the specimen cross-section varies between 0.005 and 0.011. The boride phase is more sensitive to the strain-rate than matrix and core. The room-temperature oxidation resistance of the steel surface is enhanced by the presence of a higher proportion of mixed-boride and the oxide layer enriched with Cr2O3. At 550 and 850 degrees C, boronized specimens have higher oxidation resistance than the non-boronized specimens, where the layer of iron-borates protects the surface. At 200 degrees C, the boronized specimen has deprived oxidation resistance. Amongst the investigated wear-parameters, the maximum and minimum wear-resistance of the boronized surface is about 46 and 8 times the wear-resistance of the non-boronized surface, respectively. A steeper drop in the tribological advantage gained by the boronizing treatment is perceived with the increase in load, especially under higher sliding speed CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: This work was partially supported by The Royal Society – UK (award "Royal Society-Newton Advanced Fellowship" - NAF\R2\192108), the French National Center for Scientific Research (CNRS), the Brazilian National Council of Scientific and Technological Development (CNPq – projects: 233194/2014-2, 465423/2014-0, and 422372/2016-1), and Research Support Foundation of the State of Rio Grande do Sul (FAPERGS – projects: 17/2551-0001052-3 and 19/2551-0000656-0). F.C. and F.G.E. are FAPESP fellows (projects 2018/24461-0 and 2019/00757-0). B.L.P., S.R.S.M, and L.M.L. are CAPES fellows. C.A.F and F.A. are CNPq fellows. A.C. and T.P. acknowledge the support from the project ?Novel nanostructures for engineering applications? No. CZ.02.1.01/0.0/0.0/16_026/0008396 and The Ministry of Education, Youth and Sports from the Large Infrastructures for Research, Experimental Development and Innovations project ?e-Infrastructure CZ – LM2018140? and the use of VESTA software Abstract: In dry sliding, the coefficient of friction depends on the material pair and contact conditions. If the material and operating conditions remain unchanged, the coefficient of friction is constant. Obviously, we can tune friction by surface treatments, but it is a nonreversible process. Here, we report active control of friction forces on TiO2 thin films under UV light. It is reversible and stable and can be tuned/controlled with the light wavelength. The analysis of atomic force microscopy signals by wavelet spectrograms reveals different mechanisms acting in the darkness and under UV. Ab initio simulations on UV light-exposed TiO2 show a lower atomic orbital overlapping on the surface, which leads to a friction reduction of up to 60%. We suggest that photocontrol of friction is due to the modification of atomic orbital interactions from both surfaces at the sliding interface CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: This work was financially supported by the Brazilian agencies FAPESP (projects 2012/10127-5 and 2019/18460-4) and FAPERGS (project 19/2551-0002288-3). Partial support of CONICET (PIP 2017-2019 GI-11220170100289CO) and UBACyT (20020170200298BA). F.C. is a FAPESP fellow, project 2018/24461-0. D.S., A.R.Z., C.A.F., and F.A. are CNPq fellows. This work is part of the PhD Thesis of D.S. The authors are indebted to C. Piacenti for his technical support. The authors acknowledge "Universidade Estadual de Campinas" (UNICAMP) for APC funding Abstract: The role played by oxygen vacancies and rare earth (RE) elements in the anatase-to-rutile (A-R) phase transformation of titanium dioxide (TiO2) is still a matter of controversy. Here, we report the A-R transformation of TiO2 thin solid films as obtained by ion beam sputtering a RE-decorated titanium target in an oxygen-rich atmosphere. The samples correspond to undoped, single-doped (Sm, Tm, and Tb), and codoped (Sm:Tb, Sm:Tm, and Sm:Tb:Tm) TiO2 films. In the as-prepared form, the films are amorphous and contain similar to 0.5 at. % of each RE. The structural modifications of the TiO2 films due to the RE elements and the annealing treatments in an oxygen atmosphere are described according to the experimental results provided by Raman scattering, X-ray photoelectron spectroscopy, and optical measurements. The A-R transformation depends on both the annealing temperature and the characteristics of the undoped, single-doped, and codoped TiO2 films. As reported in the literature, the A-R transformation can be inhibited or enhanced by the presence of impurities and is mostly related to energetic contributions. The experimental results were analyzed, considering the essential and stabilizing role of the entropy of mixing in the A-R transformation due to the introduction of more and multiple quantum states originated in vacancies and impurities in the anatase phase FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS Aberto

Agradecimentos: This work was supported partially by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Project 2012/10127-5 and the Instituto Nacional de Engenharia de Superficies (INES). LFZ, CF, and FA are CNPq fellows. During the development of this paper, MJMJ and VA were CAPES fellows. The authors are grateful to the LNNano, where the SEM measurements were performed. Special thanks go to C. Piacenti for his technical support Abstract: Nanostructured CrN thin films are obtained by combining RF physical vapor and dynamic glancing angle deposition using a computer-controlled substrate oscillatory motion. By using an appropriate frequency for substrate oscillation, it becomes feasible to tailor the physical properties of thin films deposited onto the substrate. The films are deposited by moving the substrate back and forward between specified angles with, among other parameters, a controlled time-dependent angular position phi(t) of the substrate. Thus, the direction of atoms striking the film changes in accordance to the position of the substrate. In this paper, we report the physical properties of a material for a varying frequency of substrate oscillation while maintaining the same angular phi(t) function (triangular function) in all the studied samples. By controlling the incidence angle phi(t) for precursor atoms impinging upon the substrate, one can prompt the formation of wavy-like periodic columnar nanostructures. The physical characteristics of the coating such as morphology, residual stress, nanohardness, crystallite size, composition, and texture of the columnar periodic multistructured films are all remarkably dependent on the oscillation frequency. The cited physical properties obtained by moving the substrate forward and back with an angular phi(t) triangular function and several periods of oscillation are reported and analyzed FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Projects 14/23399-9 and 18/08543-7. I. D. B. acknowledges the financial support from the Brazilian Nanocarbon Institute of Science and Technology (INCT/Nanocarbono) and Brazilian Synchrotron Light Laboratory (LNLS). L. F. Z. thanks Dr. Eric Le Moal (ISMO) and Dr. Mathieu Kociak (LPS) for valuable and insightful discussions which were exceedingly helpful to this research Abstract: We have studied the excitonic properties of exfoliated tungsten diselenide (WSe2) monolayers transferred to gold substrates using the tunneling current in a Scanning Tunneling Microscope (STM) operated in air to excite the light emission locally. In obtained spectra, emission energies are independent of the applied bias voltage and resemble photoluminescence (PL) results, indicating that, in both cases, the light emission is due to neutral and charged exciton recombination. Interestingly, the electron injection rate, that is, the tunneling current, can be used to control the ratio of charged to neutral exciton emission. The obtained quantum yield in the transition metal dichalcogenide (TMD) is similar to 5 x 10(-7)photons per electron. The proposed excitation mechanism is the direct injection of carriers into the conduction band. The monolayer WSe(2)presents bright and dark defects spotted by STM images performed under UHV. STS confirms the sample as p-doped, possibly as a net result of the observed defects. The presence of an interfacial water layer decouples the monolayer from the gold support and allows excitonic emission from the WSe(2)monolayer. The creation of a water layer is an inherent feature of the sample transferring process due to the ubiquitous air moisture. Consequently, vacuum thermal annealing, which removes the water layer, quenches excitonic luminescence from the TMD. The tunneling current can locally displace water molecules leading to excitonic emission quenching and to plasmonic emission due to the gold substrate. The present findings extend the use and the understanding of STM induced light emission (STM-LE) on semiconducting TMDs to probe exciton emission and dynamics with high spatial resolution FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: This work was supported by the Sao Paulo Research Foundation (FAPESP), grants #2019/18460–4 and #2018/24461–0, FAPERGS, grants #17/2551-0001052-3 and #19/2551-0002288-3, and CNPq, grant #422372/2016–1. FC is FAPESP fellow. MJMJ and LML are CAPES fellows. CAF and FA are CNPq fellows. The authors would like to thank the technician R.B. Merlo for the annealing experiments execution and R. Marcon for his help in XRD treatment data. Abstract: The vast, unexplored chemical realm of multi-principal element alloys (MPEAs) has encouraged researchers to design and synthetize advanced materials based on refractory metals, metalloids, and deoxidizer elements, that are expected to follow single-phase, solid solution high-entropy alloys (HEAs)’ footsteps. In this paper, we have theoretically and experimentally studied the AlSiTaTiZr alloy in the thin film form, due to potential applications as a high-temperature oxidation-resistant coating. The MPEA film, synthetized by radio-frequency magnetron sputtering (RFMS), shows a considerable glass-forming ability. However, the metallic glass structure transits to several intermetallic compound phases by post-thermal annealing at ~873 K, confirming that both thermodynamics and kinetics determine the formation of phases in sputtered MPEAs. Moreover, a strong tendency of Si and Al to form compounds with transition metals was revealed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and thermodynamic investigations. Special focus is given to the role played by both entropy and enthalpy on the phase evolution, demonstrated by thermodynamic calculations using the regular solution model and the CALculation of PHAse Diagrams (CALPHAD) method. This methodology is presented as a useful approach for starting deeper thermodynamic investigations in the thin film literature of MPEAs and HEAs, currently focused on the ultimate properties of such alloys FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: Authors are grateful to FAPESP (projects 2014/03691-7 and 2014/25979-2), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq—Brasil), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES—Brasil) for financial support Abstract: Reduced graphene oxide (rGO) layers are known to be significantly conductive along the basal plane throughout delocalized sp(2) domains Defects present in rGO implies in disordered systems with numerous localized sites, resulting in a charge transport governed mainly by a 2D variable range hopping (VRH) mechanism These characteristics are observed even in multilayered rGO since the through-plane conduction is expected to be insubstantial. Here, we report on the multilayer assembly of functionalized rGO quantum dots (GQDs) presenting 3D VRH transport that endows elevated charge carrier mobility, ca similar to 236 cm(2) V(-1 )s(-1). Polyelectrolyte-wrapped GQDs were assembled by layer-by-layer technique (LbL), ensuring molecular level thickness control for the formed nanostructures, along with the adjustment of the film transparency (up to 92% in the visible region). The small size and the random distribution of GQDs in the LbL structure are believed to overcome the translational disorder in multilayered films, contributing to a 3D interlayer conduction that enhances the electronic properties. Such high-mobility, transparency-tunable films assembled by a cost-effective method possess interesting features and wide applicability in optoelectronics FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: The authors gratefully acknowledge support from FAPESP (the Sao Paulo Research Foundation, Processes 2017/11986-5 and 2012/10127-5), Shell, the strategic importance of the support given by ANP (Brazil’s National Oil, Natural Gas and Biofuels Agency) through the R&D levy regulation and the Brazilian research funding agencies INCT/INES/CNPq (grant 465423/2014-0). F.A., F.C.M., N.F.C, S.C. and J.M.C.S.F. thank CNPq (grant 302370/2015-3, 306297/2017-5, 147473/2014-4, 153029/2013-7 and 103203/2018-4 respectively). This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. We would also like to thank the multi-user laboratory of the Gleb Wataghin Physics Institute (LAMULT) for the XRD measurements, CCS/UNICAMP for SEM images and IQ/UNICAMP for PL measurements. The authors are also grateful to Dr. Gustavo Viana, Rodrigo Szostak and Diego Scolfaro da Silva for the fruitful discussions had with them Abstract: Bismuth triiodide (BiI3) has been studied in recent years with the aim of developing lead-free semiconductors for photovoltaics. It has also appeared in X-ray detectors due to the high density of the Bismuth element. This material is attractive as an active layer in solar cells, or may be feasible for conversion into perovskite-like material (MA(3)Bi(2)I(9)), being also suitable for photovoltaic applications. In this study, we report on the thermomechanical properties (stress, hardness, coefficient of thermal expansion, and biaxial and reduced Young's moduli) of BiI3 thin films deposited by thermal evaporation. The stress was determined as a function of temperature, adopting the thermally induced bending technique, which allowed us to extract the coefficient of thermal expansion (31 x 10(-6) degrees C-1) and Young's biaxial modulus (19.6 GPa) for the films. Nanohardness (similar to 0.76 GPa) and a reduced Young's modulus of 27.1 GPa were determined through nanoindentation measurements CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: Author (DS) thanks IIT Indore for providing scholarship to do Ph.D. research. This work was partially supported by the SERB [grant number EMR/2017/001196]. Their support is kindly acknowledged Abstract: The surface behaviour of surface mechanical attrition treated (SMATed) and plasma-nitrided AISI 2205 and AISI 304L steels was investigated in the present study. The intersection of the mechanical twins formed the submicron-size rhombic blocks in the surface region of the SMATed AISI 304L steel. However, such microstructural feature was absent in the SMATed AISI 2205 steel. The improvement in the surface-hardness due to the SMAT was about 70-80% for AISI 2205, and more than 100% for AISI 304L steel. The nature of passive film formed on the AISI 2205 steel was different from the AISI 304L steel. Passive film formed on the SMATed AISI 304L steel was relatively more unstable than that of the AISI 2205 steel at an elevated electric-potential and in a plasma environment. The plasma-nitriding response was affected due to the different passivation behaviour of the SMATed, and non-SMATed steels Fechado

Agradecimentos: This work was supported partially by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Project 2012/10127-5 and the Instituto Nacional de Engenharia de Superficies (INES). MJMJ, ARJr, LFZ, CF, and FA are CNPq fellows. During the development of this paper VA, SC were CAPES fellows. The authors are grateful to the LNNano where the SEM measurements were performed. Especial thanks to R. Droppa Jr. for his comments about the XRD results and to C. Piacenti for the technical support. S. C. present address: IFM, UFP, PO Box 354, 96010970, Pelotas, RS, Brazil Abstract: The CrN films were grown by rf-magnetron sputtering using a dynamic glancing angle deposition technique. In this technique, the substrate oscillates in front of the sputtering target with an angular amplitude and frequency commanded by a Programmable Logic Controller. The purpose of this paper is to study the physical properties of the CrN coatings deposited on crystalline silicon by using a square and linear dependence on time of the angle of oscillation of the substrate. The angular dependence of the atoms impinging on the substrate during the oscillation modified the flux and momentum transference to the films, forming a columnar wavy-like periodic structure depending on the customized oscillatory function. The influence of the oscillation on the physical properties of the materials such as morphology, residual stress, nano-hardness, crystallite size and texture of the columnar multi-components are reported. The angular dependence of the deposition technique opens the possibility to control, according to the specific application, the nanostructure, the of the hard coatings, the periodicity of the columnar films, the deposition rate of each period as well as the uniformity of the thickness of the CrN films. The technique can be applied to other hard coatings as well (e.g., TiN, TiCN and TiAIN). The flux F of atoms arriving on the substrate has a F similar to cos phi dependence on the impinging angle phi of the precursors. Considering that the compressive stress in hard coatings deposition depends, among other things, on both the substrate external bias and deposition rate, the technique offers a potentially useful possibility to tailor the compressive stress as well, which will be the subject of further research and applications COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors are grateful to UCS, INCT-INES (# 465423/2014-0) and Plasmar Tecnologia Ltda. for financial support, LCMIC-UCS for microscopy facilities, Epipolé Research Group and N.J.S.F. and M.E.H.M.C. from PUC Rio for Raman analysis support. A.E.C., L.M.L., V.A., B.L.P., F.A., and C.A.F. are CNPq or CAPES fellows. Thanks also go to the co-authors for their unlimited moral fiber that made this study come true Abstract: Hydrogenated amorphous carbon thin films (a-C:H) have attracted much attention because of their surprising properties, including ultralow friction coefficients in specific conditions. Adhesion of a-C:H films on ferrous alloys is poor due to chemical and physical aspects, avoiding a widespread application of such a film. One possibility to overcome this drawback is depositing an interlayer-an intermediate thin film-between the carbon-based coating and the substrate to improve chemical interaction and adhesion. Based on this, interlayers play a key role on a-C:H thin-film adhesion through a better chemical network structure at the outermost layer of the a-SiCx:H interlayer, i.e., the a-C:H/a-SiCx:H interface. However, despite the latest important advances on the subject, the coating adhesion continues being a cumbersome problem since it depends on multifactorial causes. Thus, the purpose of this paper is to report a standard protocol leading to surprising good results based on the control of the interfacial chemical bonding by properly biasing the substrate (between 500 and 800 V) during the a-SiCx:H interlayer deposition at an appropriate low temperature, by using hexamethyldisiloxane as precursor. The interlayers and the outermost interfaces were analyzed by a comprehensive set of techniques, including X-ray photoelectron spectroscopy, glow discharge optical emission spectroscopy, and Fourier transform infrared spectroscopy. Nanoscratch tests, complemented by scanning electron microscopy and energy-dispersive X-ray spectroscopy, were used to evaluate the critical load for delamination to certify and quantify the adhesion improvement. This study was important to identify the chemical local bonding of the elements at the interface and its local environment, including the in-depth chemical composition profile of the coating. An important effect is that the oxygen content decreases on increasing substrate bias voltage, improving the adhesion of the film. This is due to the fact that energetic ion hitting the growing interlayer breaks Si-O and C-O bonds, augmenting the content of Si-C and C-C bonds at the outermost interface of the a-SiCx:H interlayer and enhancing the a-C:H coating adhesion. Moreover, the combination of high bias voltage (800 V) and low temperature (150 degrees C) during the a-SiCx:H interlayer deposition allows good adhesion of a-C:H thin films due to sputtering of light elements like oxygen. Therefore, an appropriated bias and temperature combination can open new pathways in a-C:H thin-film deposition at low temperatures. These results are particularly interesting for temperature-sensible metal alloys, where well adhered a-C:H thin films are mandatory for tribological applications CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: Part of this work was supported by FAPESP (Project 2012/10127-5). CAF, ARZ and FA are CNPq fellows. SRSM is FAPERGS fellow. X-ray studies were obtained at the National Laboratory of Synchrotron Radiation (LNLS - Brazil). This paper is part of the PhD thesis of MM. The authors are grateful to C. Piacenti for technical assistance Abstract: In this work we report an experimental approach by combining in situ sequential top-down and bottom-up processes to induce the organization of nanosized nickel particles. The top-down process consists in xenon ion bombardment of a crystalline silicon substrate to generate a pattern, followed by depositing a similar to 15 nm titanium oxynitride thin film to act as a metallic diffusion barrier. Then, metallic nanoparticles are deposited by argon ion sputtering a pure nickel target, and the sample is annealed to promote the organization of the nickel nanoparticles (a bottom-up process). According to the experimental results, the surface pattern and the substrate biaxial surface strain are the driving forces behind the alignment and organization of the nickel nanoparticles. Moreover, the ratio between the F of metallic atoms arriving at the substrate relative to its surface diffusion mobility determines the nucleation regime of the nickel nanoparticles. These features are presented and discussed considering the existing technical literature on the subject FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS Aberto

Agradecimentos: This work was supported by the French National Center for Scientific Research (CNRS) and the Brazilian National Council of Scientific and Technological Development (CNPq, 'Ciencia sem Fronteiras') through Project No. 233194/2014-2. FC and FA are CNPq fellows. VGA is a CAPES fellow. FA and VGA acknowledge financial support from FAPESP, project 2012/10127-5. JK and UH acknowledges financial support from the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU No. 2009-00971) and the Swedish Research Council (grant VR 621-2014-4882) Abstract: High power impulse magnetron sputtering (HiPIMS) has already demonstrated great potential for synthesizing the high-energy crystalline phase of titanium dioxide (rutile Ti-O2) due to large quantities of highly energetic ions present in the discharge. In this work, it is shown that the metastable anatase phase can also be obtained by HiPIMS. The required deposition conditions have been identified by systematically studying the phase formation, microstructure and chemical composition as a function of mode of target operation as well as of substrate temperature, working pressure, and peak current density. It is found that films deposited in the metal and transition modes are predominantly amorphous and contain substoichiometric TiOx compounds, while in compound mode they are well-crystallized and present only O2- ions bound to Ti4+, i.e. pure TiO2. Anatase TiO2 films are obtained for working pressures between 1 and 2 Pa, a peak current density of similar to 1 A cm(-2) and deposition temperatures lower than 300 degrees C. Rutile is favored at lower pressures (< 1 Pa) and higher peak current densities (gt;2 A cm(-2)), while amorphous films are obtained at higher pressures (greater than or similar to 5 Pa). Microstructural characterization of selected films is also presented CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: This work was supported by ANPCyT PICT-2012-1167, UBACyT 20020170200298BA, and CONICET-PIP_11220170100289CO. We are indebted to the program "Exactas con la Sociedad" that promoted this cooperative work with FASINPAT, including DO and CS student fellowships. R.J.C. and S.A.B. thank Jorge Bermudez and Carlos Diaz for their technical support at FASINPAT-Zanon (Parque Industrial Neuquen) and Carolina Ortega for the first successful coated tiles. M.P., M.C.M., R.J.C., and S.A.B. are members of CONICET Abstract: Self-cleaning coatings are advanced materials for the removal of pollutants and microorganisms by combining wettability, photocatalytic degradation, and antimicrobial activity. In this work, we propose a rational design of self-cleaning films based on TiO2 synthesized by sol-gel on commercial glazed ceramic tiles for building's indoor applications. The synthesis strategy is based on hydrolysis and condensation of Ti-isopropoxide in the presence of W(VI) precursors to tune defects and crystallinity of the resulting W-TiO2 thin film. From the microstructure and surface composition analysis for different tungsten contents and annealing temperatures, we conclude that the film is composed by sintered TiO2 particles with adsorbed polytungstates (WOx) that inhibit anatase/rutile transformation. Polytungstates on TiO2 also induce surface defects that enhance water contact angle and inactivation of Escherichia coli under visible light. The presence of W(VI) has a negligible effect toward crystal violet degradation either under visible or under UV light. These results provide evidence on the existence of at least two different types of defects: (i) intrinsic defect from a sol-gel route and (ii) induced defect by tungsten species on the surface. Understanding the correlation between composition, structure, and self-cleaning properties provides a base for an efficient design of low-cost self-cleaning ceramic tiles that can be fully manufactured in an industrial plant Aberto

Agradecimentos: This work is supported by the UCS, INCT-INES (# 465423/2014-0), FAPERGS. F.G.E., C.D.B., L.M.L., M.E.H.M.C., F.L.F.Jr, F.A. and C.A.F. are CNPq and CAPES fellows. S.R.S.M. is FAPERGS fellow. F.G.E. acknowledges support through of the Plasmar Tecnologia Ltda with sponsored Ph.D. studentship at the Universidade de Caxias do Sul. F.A. is indebted to FAPESP, project 2012/10127-5. The authors thank their colleagues and collaborators who participated in the preparation, testing, and characterization of the a-C:D/H and a-C:H thin films discussed in this work Abstract: Lateral force microscopy (LFM) is an established technique to assess friction forces at the nanoscale. Nanoindentation followed by unidirectional sliding (NUS) is also used to evaluate friction forces at the micro/nanoscale. However, comparative studies between NUS and LFM evaluating the experimental results at different scales are still missing. In this work, a-C:D/H and a-C:H thin films with different [D]/[C] and [H]/[C] contents were used to analyze the friction forces by NUS and LFM. The results show that the friction behavior assessed by these two techniques in different scales is the same. The correlation between friction forces measured by NUS and LFM depends mainly on a contact area factor that makes invariant the friction force from nanoscale to microscale. Such behavior suggests a similar damping mechanism, probably phonon-coupling phenomena, for the friction force origin CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: This work is supported by the UCS, INCT-INES (CNPq) (465423/2014-0), CAPES (BRAFITEC 087/11), and FAPERGS. F. G. E., L. M. L., M. E. H. M. C., F. A. and C. A. F. are CNPq and CAPES fellows. S. R. S. M. is FAPERGS fellow. F. G. E. acknowledges support through of the Plasmar Tecnologia Ltda with sponsored PhD studentship at the Universidade de Caxias do Sul. F. A. is indebted to FAPESP, project 2012/10127-5. The authors thank their colleagues and collaborators who participated in the preparation, testing, and characterization of the a-C:H thin films discussed in this paper Abstract: Hydrogenated amorphous carbon (a-C:H) thin films have a unique combination of properties that are fundamental in mechanical and electromechanical devices aimed at energy efficiency issues. The literature brings a wealth of information about the ultra-low friction (superlubricity) mechanism in a-C:H thin films. However, there is persistent controversy concerning the physicochemical mechanisms of contact mechanics at the atomic/molecular level and the role of electrical interactions at the sliding interface is still a matter of debate. We find that the hydrogenation of the outermost nanostructured surface atomic layers of a-C:H thin films is proportional to the surface potential and also to the friction forces arising at the sliding interface. A higher hydrogen-to-carbon ratio reduces the surface potential, directly affecting frictional forces by a less effective long-term interaction. The structural ultra-low friction (superlubricity) is attributed to a lower polarizability at the outermost nanostructured layer of a-C:H thin films due to a higher hydrogen density, which renders weaker van der Waals forces, in particular London dispersion forces. More hydrogenated nanodomains at the surface of a-C:H thin films are proposed to be used to tailor superlubricity CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The Authors would like to thank MAHLE Metal Leve and BNDES (Decision Dir. 640/2012) for funding. MCRG, BCNMC and PRTA acknowledge the Brazilian agencies CAPES and CNPq for the scholarships. The authors would like to thank Carlos Cunha for operating the deposition chamber. Furthermore, the Authors would like to thank Wagner Correr, from the Sao Carlos Institute of Physics, University of Sao Paulo, for all the help with images, discussions and equipments. HP is a CNPq fellow. This work was supported by the CREATE-Network Project, Horizon 2020 Program of the European Commission (RISE Project No 644013). H. Pinto and J. Garcia thanks the financial support of the project Create-Net Project No 318903 financed by the EU Agradecimentos: The Authors would like to thank MAHLE Metal Leve and BNDES (Decision Dir. 640/2012) for funding. MCRG, BCNMC and PRTA acknowledge the Brazilian agencies CAPES and CNPq for the scholarships. The authors would like to thank Carlos Cunha for operating the deposition chamber. Furthermore, the Authors would like to thank Wagner Correr, from the Sao Carlos Institute of Physics, University of Sao Paulo, for all the help with images, discussions and equipments. HP is a CNPq fellow. This work was supported by the CREATE-Network Project, Horizon 2020 Program of the European Commission (RISE Project No 644013). H. Pinto and J. Garcia thanks the financial support of the project Create-Net Project N° 318903 financed by the EU Abstract: There are plenty of deposition techniques to produce hard coatings. Among them, Direct Current Magnetron Sputtering (dcMS) and High Power Impulse Magnetron Sputtering (HiPIMS) are known to produce dense coatings with few or no growth defects. Transition metal nitrides are widely used for tribological applications. CrN has been described as a high hardness, high wear resistant coating therefore making an ideal candidate to be deposited by sputtering. Although the use of multilayers have been described as a mean to further increase wear resistance, no study has presented the effect of a multilayer produced by the oscillation of the substrate during the deposition process. This paper presents a study of the effect of the oscillation on the production of these multilayer and its effects on the mechanical and structural properties of the coating. Furthermore, the effects of bias and frequency on these properties were evaluated. To characterize the coatings it was used XRD, SEM, AFM, Nanohardness and Corrosion tests. The XRD results showed higher texture on (311) plane for -60 V for HiPIMS deposition for all frequencies leading to higher hardness. Compressive residual stresses were found to grow as the bias increased for HiPIMS deposition, whereas dcMS led to the opposite behavior. Finally, dcMS coatings presented similar corrosion resistance when compared to HiPIMS coatings COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: Part of this work was supported by FAPESP, grant 2012/10127-5. VGA, CF and FA are CNPq – Brazil fellows. VGA is CAPES fellow. This paper is part of the Ph.D. thesis of VGA. The authors are grateful to C. Piacenti for technical help Abstract: In this paper, a comprehensive X-ray photoelectron spectroscopy (XPS) study of the first atomic layers of TiN nanofilms grown by ion beam assisted deposition on crystalline silicon is reported. This deposition technique allows a fine control of the ion species and energy arriving at the substrate. The substrates are prepared by ion beam cleaning involving Xe+ ion bombardment in different partial pressures of molecular H2. The expected hydrogen passivation effect by the Si-H formation bond limiting the Si-O bonds was quantitatively evaluated and correlated with some retention of H and O at the substrate surface. The effects of molecular H2 and residual H2O atmosphere present during the process on the chemical bonding on both the naked Si substrate and afterward on the interface are reported. A detailed XPS analysis performed in an attached UHV chamber to the preparation chamber of the TiN/Si interface shows that the bombarding cleaning procedure plays an important role in the bond formation at the interface since minute amounts the oxygen jeopardize the bulk properties FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: The Authors would like to thank MAHLE Metal Leve and BNDES (Decision Dir. 640/2012) for funding. MCRG and BCNMC acknowledge CAPES and CNPq for the scholarships. HP is a CNPq fellow Abstract: Hard coatings are a suitable solution for increasing the lifetime of tools and components employed in different industrial applications. Coatings of transition metal nitrides have great use for tribological applications due to due to their unique mechanical properties. Although widely employed, current deposition methods such as cathodic arc evaporation produce coatings with many defects, which in turn reduce the resistance to wear, especially under severe conditions. High Power Impulse Magnetron Sputtering is a novel physical vapor deposition technique that produces homogeneous coatings. In this study, CrN and CrAlN monolayer coatings were deposited on AISI 304 stainless steel substrates using HiPIMS. X-Ray Diffraction, Scanning Electron Microscopy, Atomic Force Microscopy were used to evaluate the microstructure, phase composition, morphology and chemical composition of the coating. Results showed that HiPIMS is a promising technique to deposit CrN and CrAlN homogeneous coatings with high hardness and good adhesion to the substrate COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: The authors are grateful to UCS, INCT-INES (CNPq - Grant # 465423/2014-0), CAPES (Grant BRAFITEC 087/11), and FAPERGS (Grant # 1014707) for financial support. NBJr., CMM, FBC, FA, CAP and CAF are CNPq, FAPERGS or CAPES fellows. FA is supported by FAPESP project 2012/10127-5 Abstract: Fundamental understanding of friction forces at the micro/nanoscale continues being a challenge in tribology. This work reports on the friction behavior of the outermost magnetite layers grown on a nitrided ferrous alloy studied by two different and independent experimental methods: nanoindentation followed by unidirectional sliding and friction force microscopy. Macroscopic mechanical properties involving hardness (H) and Young modulus (E), such as the plastic deformation parameter (H-3/E-2) and the elastic strain to failure (H/E), as well as surface roughness cannot explain the lack of influence of the friction coefficient on the outermost magnetite layer thickness. Moreover, the observed energy dissipation phenomenon is consistent with phononic non-conservative damping forces CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors are grateful to UCS, INCT-INES (# 554336/2010-3), CAPES (Brafitec 087/11), FAPERGS and Plasmar Tecnologia Ltda. for financial support. A.E.C., L.M.L., C.A., F.A., and C.A.F. are CNPq or CAPES fellows. FA was supported by FAPESP project 2012/10127-5. The authors would like to thank to LCMIC-UCS for microscopy facilities and S.S.C. Jr for helping A.E.C. in the nanoscratch measurements Abstract: Carbonaceous thin films show poor adhesion when deposited on steels. Chromium, titanium, and silicon containing interlayers are generally used in order to prompt adhesion. This work shows a systematic study of the hydrogen effect on the physical-chemical properties of a-SiCx:H interlayers deposited by using hexamethyldisiloxane on AISI 4140 at low temperatures (85 degrees C-180 degrees C). In particular, the effect of the treatment on the adhesion of a-C:H thin films is reported. The results show that hydrogen radically modifies the tribological behavior inducing the adhesion of a-C:H thin films at temperatures as low as 85 degrees C. The adhesion's improvement is associated with the hydrogen chemical etching that seems to remove more silicon than carbon atoms from the outermost face of the a-SiCx:H interlayer promoting the formation of stronger carbon-carbon bonds. The results are also discussed showing the efficiency obtained by the use of the electrostatic confinement deposition technique CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors are grateful to UCS, INCT-INES-CNPq (Grant #554336/2010-3), CAPES (Grant #Brafitec 087/11, FAPERGS and SUMA2 Network Project - 7th Framework Program of the European Commission (IRSES Project #318903) for financial support. SRSM is FAPERGS fellow. CMM is CAPES fellow. MEHMC, FLF, FA, and CAF are CNPq fellows. FA was supported by FAPESP project 2012/10127-5 Abstract: The friction phenomenon is a ubiquitous manifestation of nature. Models considering phononic, electronic, magnetic, and electrostatic interactions are invoked to explain the fundamental forces involved in the friction phenomenon. In order to establish the incidence of the phonon prompting at the nanoscale friction by direct contact, we study a diamond spherical dome sliding on carbon thin films containing different amount of deuterium and hydrogen. The friction coefficient decreases by substituting hydrogen by deuterium atoms. This result is consistent with an energy dissipation vibration local mechanism from a disordered distribution of bond terminators CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: Part of this work was supported by FAPESP, Project No. 2012/10127-5. S.C., C.A.F., and F.A. are CNPq fellows. SEM images were obtained at the Brazilian Nanotechnology National Laboratory, Campinas, SP (LNNano). The authors are grateful to Dr. D. Apel and Dr. M. Meixner for their help in the stress measurements and to C. Piacenti for technical help Abstract: The effect of low energy (

Agradecimentos: The authors HP and JG acknowledge the financial support of the NanoCom Network (Proposal FP7 n° 247524) and the CREATe-Network project (H2020-MSCA-RISE/644013), both funded by the European Union. SV is grateful to Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Comissão de Aperfeiçoamento de Pessoal do Nível Superior (CAPES) for granting the scholarship for acting in this research. FA and HP are CNPq fellows. Part of this work was supported by FAPESP, projects 2010/11391-2 and 2012/10127-5. The Brazilian Nanotechnology National Laboratory (LNNano) is greatly acknowledged for support during the TEM analyses Abstract: In this paper the influence of pre-treating a 100Cr6 steel surface by Xe+ ion bombardment and plasma nitriding at low temperature (380 degrees C) on the roughness, wear resistance and residual stresses of thin TiN coatings deposited by reactive IBAD was investigated. The Xe+ ion bombardment was carried out using a 1.0 keV kinetic energy by a broad ion beam assistance deposition (IBAD, Kaufman cell). The results showed that in the studied experimental conditions the ion bombardment intensifies nitrogen diffusion by creating lattice imperfections, stress, and increasing roughness. In case of the combined pre-treatment with Xe+ ion bombardment and subsequent plasma nitriding, the samples evolved relatively high average roughness and the wear volume increased in comparison to the substrates exposed to only nitriding or ion bombardment CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors are grateful to UCS, INCT-INES (#554336/2010-3), CAPES (Brafitec 087/11), FAPERGS, CNPq-PETROBRAS (#166687/2014-6) and Plasmar Tecnologia Ltda. for financial support. FC, LTB, CMM, MEHMC, IJRB, FA, and CAF are CNPq and CAPES fellows. FC is in part supported by PETROBRAS (#166687/2014-6). FA is in part supported by FAPESP project (2012/10127-5). This work was supported by the SUMA2 Network Project, 7th Framework Program of the European Commission (IRSES Project # 318903) Abstract: Diamond-like carbon (DLC) is a hydrogenated amorphous carbon (a-C:H) thin film material owing to its unique tribological properties that may open great opportunities for new applications. However, DLC presents low chemical affinity with metallic alloys and high intrinsic stress, prompting film delamination and poor adherence on the substrate. In the present work, we performed a systematic study about structural and tribological properties of a-C:H thin films grown on steel by introducing adhesive silicon-containing interlayers deposited at different processing temperatures and times. The studied bi-layers were deposited by electrostatic confinement plasma enhanced chemical vapor deposition (EC-PECVD) and were characterized by several techniques. The results showed that the adhesive interlayers produced from tetramethylsilane are chemically structured as a non-stoichiometry hydrogenated amorphous silicon carbide alloy (a-SiCx:H). Its structure, chemical composition and thickness are very dependent on deposition conditions. The thickness of the interlayers increases with deposition time and decreases with deposition temperature. The interlayer contains less hydrogen and silicon atoms at higher deposition temperatures, with enhanced formation of Si-C bonds in its structure. This last chemical event is correlated with the rise in the critical load values found for a-C:H film delamination when the a-SiCx:H interlayers are deposited from 573 K to 823 K. On the other hand, the interlayer contains less carbon atoms at higher deposition times, decreasing the critical load values for a-C:H film delamination when the a-SiCx:H interlayers are deposited from 5 min to 10 min COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: This work was supported by the NanoCom Network Project, 7th Framework Program – IRSES – Project Nr. 247524. SSV, FA and HP are CNPq fellows Abstract: In this paper we studied the influence of pre-treating the surface of 100Cr6 steel by ion beam nitriding at low temperature (380 degrees C) on the surface topography and wear resistance of thin TiN coatings deposited by reactive ion beam assisted deposition. The specimens were characterized by grazing incidence X-ray diffraction, scanning electron microscopy and atomic force microscopy. The wear resistance of the TiN-coated specimens was evaluated by means of ball on disc tests. The results showed that application of a preliminary ion beam nitriding treatment slightly increased the surface roughness but improved the wear resistance of the 100Cr6 steel due to the formation of a diffusion zone containing the gamma'-Fe4N nitride combined with the TiN coating CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: This work is part of the Master degrees requirements of SC. The authors are grateful to C. Piacenti for technical help. Part of this work was supported by FAPESP, project 2012/10127-5. SC is a FAPESP fellow. FA, LFZ and EAO are CNPq fellows. SEM images were obtained at the Brazilian Nanotechnology National Laboratory (LNNano). The DRX were performed at the Brazilian Synchrotron Light Laboratory (LNLS) Abstract: The modification of steel (AISI 316L and AISI 4140) surface morphology and underlying inter-crystalline grains strain due to Xe+ ion bombardment are reported to affect nitrogen diffusion after a pulsed plasma nitriding process. The ion bombardment induces regular nanometric patterns and increases the roughness of the material surface. The strain induced by the noble gas bombardment is observed in depths which are orders of magnitude larger than the projectiles' stopping distance. The pre-bombarded samples show peculiar microstructures formed in the nitrided layers, modifying the in-depth hardness profile. Unlike the double nitrided layer normally obtained in austenitic stainless steel by pulsed plasma nitriding process, the Xe+ pre-bombardment treatment leads to a single thick compact layer. In nitrided pre-bombarded AISI 4140 steel, the diffusion zone shows long iron nitride needle-shaped precipitates, while in non-pre-bombarded samples finer precipitates are distributed in the material FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Aberto

Agradecimentos: The authors are grateful to UCS, INCT-INES (# 554336/2010-3), CAPES (Brafitec 087/11), PETROBRAS (504062/2014-0), and FAPERGS for financial support. F.C., L.T.B., L.M.L., I.J.R.B., F.A., and C.A.F. are CNPq and CAPES fellows. F.A. is, in part, supported by Fapesp project 2012/10127-5. F.C. is partly supported by PETROBRAS. This work was supported by the SUMA2 Network Project, seventh Framework Program of the European Commission (IRSES Project # 318903). Finally, the authors are grateful to M. E. H. Maia da Costa at PUC-Rio for the Raman spectra Abstract: Amorphous carbon (a-C) and several related materials (DLCs) may have ultralow friction coefficients that can be used for saving-energy applications. However, poor chemical bonding of a-C/DLC films on metallic alloys is expected, due to the stability of carbon-carbon bond's. Silicon-based intermediate layers are employed to enhance the adherence of a-C:H films on ferrous alloys, although the role of such buffer layers is not yet fully understood in chemical terms. The chemical bonding of a-C:H thin films on ferrous alloy intermediated by a nanometric SiCx:H buffer layer was analyzed by X-ray photoelectron spectroscopy (XPS): The chemical profile was inspected by glow discharge optical emission spectroscopy (GDOES), and the chemical structure was evaluated by Raman and Fourier transform infrared spectroscopy techniques. The nature of adhesion is discussed by analyzing the chemical bonding at the interfaces of the a-C:H/SiCx:H/ferrous alloy sandwich structure. The adhesion phenomenon is ascribed to specifically chemical bonding character at the buffer layer. Whereas carbon carbon (C-C) and carbon silicon (C-Si) bonds are formed at the outermost interface, the innermost interface is constituted mainly by silicon iron (Si-Fe) bonds. The oxygen presence degrades the adhesion up to totally delaminate the a-C:H thin films. The SiCx:H deposition temperature determines the type of chemical bonding and the amount of oxygen contained in the buffer layer CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: Part of this work was supported by FAPESP, project No. 05/53926-1. FA and EO are CNPq fellows. The authors are indebted to C. Piacenti for technical help. The XRD measurements were performed at the XRD1 beamline of the Brazilian Synchrotron Light Laboratory (LNLS). The AFM measurements were performed at the Multiuser Experimental Center of UFABC. SEM measurements were carried out at the Brazilian Nanotechnology National Laboratory (LNNano). J. Garcia and H. Pinto acknowledge the financial support of the Nanocom Network, 7th Framework program-IRSES- Project No. 247524 Abstract: The effect of ion-beam bombardment with low energy Xe ions on the physical properties of 100Cr6 steel is reported. The modified region induced by the relative low energy ions (

Agradecimentos: The authors are grateful to UCS, INCT-INES (CNPq), CAPES, FAPERGS for financial support. C.M.M., F.B.C., P.A.F., F.C., I.J.R.B., FA, and C.A.F. are CNPq and CAPES fellows. F.A. is in part supported by Fapesp Project 2012/10127-5 Abstract: Friction is a ubiquitous phenomenon in everyday activities spanning from vehicles where efficient brakes are mandatory up to mechanical devices where its minimum effects are pursued for energy efficiency issues. Recently, theoretical models succeed correlating the friction behavior with energy transference via phonons between sliding surfaces. Therefore, considering that the energy losses by friction are prompted through phonons, the chemical surface structure between sliding surfaces is very important to determine the friction phenomenon. In this work, we address the issue of friction between a conical diamond tip sliding on different functionalized flat steel surfaces by focusing the influence of the chemical bonds in the outermost layers on the sliding resistance. This geometry allows probing the coupling of the sharp tip with terminator species on the top and underneath material surface at in-depth friction measurements from 20 to 200 nm. Experimentally, the friction coefficient decreases when nitrogen atoms are substituted for oxygen in the iron network. This effect is interpreted as due to energy losses through phonons whilst lower vibrational frequency excitation modes imply lower friction coefficients and a more accurate adjustment is obtained when a theoretical model with longitudinal adsorbate vibration is used CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SUL - FAPERGS FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Aberto

Agradecimentos: Part of this work was supported by FAPESP, project # 2013/12501-4. FA, CAF, LFZ and MM are CNPq and Capes fellows, respectively. The authors are indebted to the Brazilian Synchrotron Light Laboratory (LNLS) where the grazing X-ray experiments were performed Abstract: The low energy (similar to 50-350 eV) noble gases ion bombardment of the steel surface shows that the pre-treatments increase nitrogen diffusion by modifying the outermost structure of the material. The surface microstructure and morphology of the studied samples were characterized by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The crystalline and chemical structures in the outermost layers of the surface were analyzed by grazing angle X-ray diffraction (GAXRD) and photoemission electron spectroscopy (XPS). Temperature effusion studies of the implanted ions are used to elucidate the noble gases site localization in the network. The local compressive stress induced by the nearby iron atoms on the core level electron wave functions of the trapped noble gases are studied by photoemission electron spectroscopy (XPS) and interpreted considering a simple mechanical model. Nano-hardness measurements show the dependence of the material elastic constant on the energy of the implanted noble gases. Although the ion implantation range is about few nanometers, the atomic attrition effect is larger enough to modify the material structure in the range of micrometers. Two material stress zones were detected where the outermost layers shows compressive stress and the underneath layers shows tensile stress. The implanted noble gases can be easily removed by heating. A diffusion model for polycrystalline-phase systems is used in order to discuss the influence of the atomic attrition on the N diffusion coefficient. The concomitant effect of grain refining, stress, and surface texture on the enhancing nitrogen diffusion effect is discussed FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: Part of this work was supported by FAPESP, project 05/53926-1. FA and LFZ are CNPq fellows. M Morales and S Cucatti are Capes and Fapesp fellows, respectively. The authors are indebted to C Piacenti for technical help Abstract: The influence of nano-structure and composition of the substrate on the properties of carbon nanotubes (CNTs) is presented. The samples are obtained following a sequential in situ deposition routine. First, TiNxOy films are grown on a crystalline silicon substrate. Immediately, dispersed nickel catalyst particles are deposited on the film. The non-stoichiometric TiNxOy films and Ni particles are grown by ion beam sputtering of Ti and Ni targets, respectively. Soon after that, the CNTs are grown by feeding acetylene gas into the chamber and maintaining the substrate at 973 K. In situ x-ray photoelectron spectroscopy allows compositional and structural analysis in all the stages of the sample growth process. The CNTs are further studied by scanning and transmission electron microscopy techniques, showing different population densities, sizes and diameters as a function of the oxygen content in the TiNxOy films. The results show that oxygen influences the surface diffusion mobility of the precursor carbon atoms involved in the growth of nanotubes suggesting the inhibition of catalyst particle coarsening. It is concluded that, in addition to acting as a diffusion barrier between the catalyst particles and the silicon support, the TiNxOy films modify the growth kinetics of the CNTs FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Agradecimentos: This work is part of the Ph.D. thesis of J.J.S.A. and was partially sponsored by Fapesp, Project No. 97/12069-0. J.J.S.A. and F.A. are CNPq fellows. C.A.F. is a FAPESP fellow (Project No. 04/01977-9). At present, C.A.F. is at the CCET, UCS, 95070-560, Caxias do Sul-RS, Brazil. The electron microscopy work has been performed with the JEOL JSM6330F (SEM-FEG) and JEOL JEM-3010 URP (HRTEM) microscopes of the LME/LNLS, Campinas, SP, Brazil Abstract: We report a comprehensive study involving the ion beam oxygen etching purification mechanism of domelike carbon nanostructures containing nitrogen. The CNx nanodomes were prepared on Si substrate containing nanometric nickel islands catalyzed by ion beam sputtering of a carbon target and assisting the deposition by a second nitrogen ion gun. After preparation, the samples were irradiated in situ by a low energy ion beam oxygen source and its effects on the nanostructures were studied by x-ray photoelectron spectroscopy in an attached ultrahigh vacuum chamber, i.e., without atmospheric contamination. The influence of the etching process on the morphology of the samples and structures was studied by atomic force microscopy and field emission gun-secondary electron microscopy, respectively. Also, the nanodomes were observed by high resolution transmission electron microscopy. The oxygen atoms preferentially bond to carbon atoms by forming terminal carbonyl groups in the most reactive parts of the nanostructures. After the irradiation, the remaining nanostructures are grouped around two well-defined size distributions. Subsequent annealing eliminates volatile oxygen compounds retained at the surface. The oxygen ions mainly react with nitrogen atoms located in pyridinelike structures FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: P. Paredez and F. Alvarez are CAPES and CNPq fellows, respectively and were partially sponsored by Fapesp, Brazil, project # 05-53926-1. The work carried out at the Joint Research Centre is financed by the JRC Action 15008 "NanoBiotechnology for Health." Abstract: Single-wall (SW-) and few-walled (FW-) carbon nanotubes (CNTs) were synthesized on aluminum/cobalt coated silicon at temperatures as low as 450 degrees C by plasma enhanced chemical vapor deposition technique (PECVD). The SWCNTs and FWCNTs grow vertically oriented and well separated from each other. The cold field emission studies of as-grown SWCNTs and FWCNTs showed low turn-on field emission threshold voltages, strongly dependent of the nanotubes morphology. Current-voltage curves of individual CNTs, measured by conductive atomic force microscopy (CAFM), showed an electrical resistance of about 90 K Omega, that is attributed mainly to the resistance of the contact between the CNTs and the conductive CAFM tip (Au and Pt) COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado

Agradecimentos: The authors are in debt to LNLS and the financial support from CAPES, FAPESP and CNPq Abstract: Electronic struture of Xe implanted in amorphous silicon (a-Si) films are investigated. Xe atoms were implanted with low energy by ion beam assisted deposition (IBAD) technique during growth of the a-Si films. The Xe implantation energy varied in the 0-300eV energy range. X-ray photoelectron spectroscopy (XPS), X-ray Auger excited spectroscopy (XAES) and X-ray absorption spectroscopy (XAS) were used for investigating the Xe electronic structure. The Xe M4N45N45 transitions were measured to extract the Auger parameter and to analyze the initial state and relaxation contributions. It was found that the binding energy variation is mainly due to initial state contribution. The relaxation energy variation also shows that the Xe trapped environment depends on the implantation energy. XAS measurements reveals that Xe atoms are dispersed in the a-Si matrix COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: This work was partially sponsored by Fapesp, project 05-53926-1. This work is part of the PP PhD thesis. PP is a CAPES fellow. MEHMC and FA are CNPq fellows. The authors are grateful to C.A. Piacenti for his technical assistance. To J. Bettini, D. Biggemann, for the TEM measurements support. To V. Pimentel for the AFM measurements help and I. Horcas for the support on WSxM 4.0 Software, Nanotec Electronica S.L. The TEM and AFM were performed at the LNLS, Campinas, Brazil Abstract: The synthesis and properties of fullerene-like carbon materials containing nitrogen deposited by ion beam sputtering in a high-vacuum chamber are reported. The samples are grown on Si substrate by sequentially depositing a titanium nitride thin film, nanometric nickel particles, and carbon. The carbon nanostructured samples were prepared by sputtering a carbon target in nitrogen and helium-nitrogen atmospheres. The effect of the noble gas on the nanostructure formation is reported. X-ray photoelectron spectroscopy performed in an ultra high-vacuum chamber, attached to the deposition system, reveals the incorporation of nitrogen in the carbon layer coating the nickel particles. Atomic force microscopy shows dome-like shaped structures. Raman spectroscopy and high-resolution transmission electron microscopy show multi-wall graphenes covering the nickel particles. The field emission properties of the structures are reported FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Agradecimentos: This work was partially sponsored by FAPESP, project # 05/53926-1. CAF is FAPESP fellow (project # 04-01977). FA is CNPq fellow. CAF is indebted to LGLS (Nancy-France) Abstract: In this paper, we study the oxygen effect in low energy nitrogen implanted stainless steel AISI 316 at different oxygen partial pressures and temperatures. The samples were studied by photoemission electron spectroscopy (XPS) and sputtered neutral mass spectrometry (SNMS). Increasing the oxygen partial pressure during nitriding decreases the nitrogen content in the material depth. Surface oxidation induces phase segregation. The presence of oxygen forms CrOx on the top most layer of the sample and, subsequently, a nickel layer appears at approximately 9-10 nm beneath the surface. Moreover, the surface oxidation reaction of metal elements depends more strongly on the oxygen atoms landing on the surface rather than on the temperature process. At higher temperatures, on the other hand, the NOx species are degraded FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ Fechado

Orientador: Fernando Alvarez Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin Resumo: Nitreto de boro hexagonal (h-BN) é formado pela alternância de átomos de nitrogênio e boro em uma rede hexagonal, onde os átomos estão ligados por ligações covalentes e as camadas por forças de interação de van der Waals (vdW). Este material, na forma de monocamada, possui alta energia de bandgap (~6 eV), enquanto que, como filme fino esse valor fica ~4,5 eV. Devido à essa propriedade, ele é comumente usado em heteroestruturas para aplicações eletrônicas e ópticas, como dispositivos emissores e detectores de UV profundo. h-BN também serve como uma interface para redução da flutuação de cargas, camada de passivação, camada dielétrica e é considerado a interface mais compatível para ancorar o grafeno. Neste estudo, filmes finos de h-BN nanoestruturados foram obtidos por pulverização catódica de rádio frequência e amostras selecionadas foram depositadas com auxílio da técnica de deposição dinâmica angular (do inglês, dinamic glancing angle deposition, DGLAD), na qual o substrato oscila em frente ao alvo numa função definida por um sistema de controlador lógico programável. Através da alteração dos parâmetros de deposição, como polarização do substrato, teor de hidrogênio na mistura gasosa constituinte do plasma e oscilação do substrato, as propriedades ópticas e estruturais desses materiais são adaptadas, o que é desejado para diferentes aplicações, como dispositivos de captura de luz e heterojunções. Os resultados obtidos mostraram a formação de filmes com estrutura turbostratic e policristalina (nanocristais). A inserção de hidrogênio no plasma durante as deposições resultou na diminuição do teor de oxigênio residual dos filmes de ~12–5% e, consequente aumento do tamanho do cristalito de ~6–16 nm, uma vez que, a diminuição do conteúdo de oxigênio favorece a formação de ligações entre boro e nitrogênio. Os valores de energia de bandgap amorfo aumentaram de ~3,7–4,2 eV para as amostras depositadas com uso de DGLAD indicando que existe uma relação direta entre o ângulo de incidência das espécies constituintes do filme na reestruturação do material, mudando as distâncias interatômicas e, consequentemente, a estrutura eletrônica de bandas. Alterações nas características morfológicas foram visíveis por microscopia eletrônica de varredura e imagens topográficas de microscopia de força atômica, indicando um perfil de crescimento típico de nanowalls. Enfim, conclui-se que a técnica DGLAD é uma rota alternativa eficaz na obtenção de materiais inovadores como h-BN permitindo um fino ajuste de suas propriedades estruturais e energia de bandgap Abstract: Hexagonal boron nitride (h-BN) is formed by alternating nitrogen and boron atoms in a hexagonal lattice, where the atoms are linked by strong covalent bonds and the layers by van der Waals (vdW) interactions forces. This material, in monolayers form has a high bandgap energy (~6 eV), while as thin films it has ~4.5 eV. Due to this property, it is commonly used in heterostructures for electronic and optical applications such as deep UV emitting devices and detectors. h-BN also serves as an interface for charge fluctuation reduction, passivation layers, dielectric layer, tunnel barrier, and it is considered the most compatible interface to anchor graphene. In this study, nanostructured h-BN thin films were obtained by radio frequency magnetron sputtering and select samples were deposited by Dynamics Glazing Angle Deposition (DGLAD) technique, in which substrate oscillates in front of sputtering target in a function defined by a Programmable Logic Controller (PLC) system. Through changing deposition parameters such as substrate polarization, hydrogen content in the gas mixture that constitutes the plasma, and substrate oscillation, optical and structural properties of these materials are adapted. That is desired for different applications, such as light capture devices and heterojunctions. The obtained results showed the formation of films with turbostratic and polycrystalline structures (nanocrystals). Hydrogen insertion into the plasma during depositions resulted in a decrease of residual oxygen content of the films by ~12–5% and, consequently, an increase in crystallite size from 6–16 nm. Decreasing oxygen content favors the formation of bonds between boron and nitrogen. Amorphous bandgap energy values increased from ~3.7 –4.2 eV for samples deposited using DGLAD indicating that there is a direct relationship between the angle of incidence of the films constituent species casing a restructuring of the material, changing interatomic distances and, consequently, the electronic band structure. Changes in morphological characteristics were visible by scanning electron microscopy and topographic images by atomic force microscopy, indicating a typical growth profile of nanowalls. Finally, it is concluded that the DGLAD technique is an effective and alternative route to obtain innovative materials such as h-BN allowing a fine tuning of their structural properties and bandgap energy Mestrado Física Aplicada Mestra em Física CAPES 88887.473650/2020-00