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• Magnetron sputtered niobium (Nb) films have been prepared by varying the deposition pressure. • Surface roughness and density of Nb films significantly change with deposition pressure. • Nb films of any stress state can be deposited by varying the deposition pressure. • The lowest electrical resistivity achieved is comparable to that of bulk Nb metal. • The micro-structural changes correlated with Nb films' mechanical and electrical properties. Niobium (Nb) thin films were deposited on a Si substrate using magnetron sputtering system by varying the deposition pressure. The effect of deposition pressure on the microstructure, residual stresses, and electrical properties was investigated by systematically varying the deposition pressure from 0.15 to 0.60 Pa. The Nb thin films were characterized using hard x-ray reflectivity, grazing incidence x-ray diffraction, four point probe method, and atomic force microscopy. The films grown at lower deposition pressures had smooth surfaces and more compact structures, which are advantageous for lowering electrical resistance but had higher compressive stress. On the other hand, the films grown at higher deposition pressures had columnar type growth with less dense structures, which leads to increase in electrical resistance. However the nature of stresses transform from compressive to tensile. Hard X-ray reflectivity performed on Nb films provides direct insight into the growth and the microstructure which were correlated with the mechanical and electrical properties. [ABSTRACT FROM AUTHOR]

• Results show that higher crystal quality is obtained using quartz substrate. • Emission properties are strongly affected by substrate and Cu thickness. • Resistivity and mobility of Al:ZnO /Cu decreases with increasing of Cu thickness. • The bilayer/glass substrate with a thickness of 13 nm Cu has the best figure of merit. In this study, using a multi-source confocal radio frequency magnetron sputtering system, we synthesized aluminum doped zinc oxide (AZO) single layers and AZO/Cu bilayers on glass and crystalline quartz substrates with a constant AZO thickness of 65 nm and variable Cu bottom layers with a thickness of 4–13 nm. The microstructural, morphological, optical, and electrical characteristics of all samples were investigated using a variety of spectroscopic techniques. The X-ray diffraction results show that all films prepared on both substrates have a hexagonal wurtzite crystal structure and exhibit the preferred orientation along the (002) plane with some microstructural variations. The atomic force microscopy images revealed that the thickness of the Cu layer and substrate type greatly affect the films' topography and surface roughness. The transmittance spectra indicate that the single AZO layer on both substrates possess the highest average visible transmission; however, all the samples deposited on glass substrates show greater transmittance than that on quartz. Photoluminescence analysis put into evidence a decrease in ultraviolet emission with Cu thickness for both substrates, with intensities varying according to substrate type. Hall Effect measurements reveal that all samples have n-type conductivity as well as that Cu thickness has a significant impact on their electrical characteristics. Moreover, a higher value of the figure of merit is achieved with the AZO/Cu bilayer structure grown on a glass substrate with 13 nm of Cu layer thickness. [ABSTRACT FROM AUTHOR]

• Y6 electron acceptor enhances conductivity via Langmuir–Schaefer method. • Langmuir–Schaefer method increases the conductivity of Y6:PM6 blend. • Langmuir–Schaefer film of Y6:PM6 blend exhibits increased surface roughness. • Film morphology and molecular packing affect device performance. • Langmuir–Schaefer method enhances the photoconductivity of the Y6:PM6 blend. This study investigates the molecular-level assembly and electronic properties of Langmuir and Langmuir–Schaefer (LS) films formed from Y6 (a non-fullerene electron acceptor) and PM6 (a wide bandgap electron donor polymer). We employ a variety of techniques including surface pressure-area isotherms, Brewster angle microscopy, ultraviolet-visible spectroscopy, Raman spectroscopy, and electrical characterizations to explore the behavior of these films. Our findings reveal that the films exhibit a tendency to aggregate and form non-homogeneous layers, which impacts their optical and electrical properties. The LS films show a significant sensitivity to solar radiation, which is evident from the changes in conductivity under illumination. This study highlights the potential of these materials in the development of photovoltaic applications, emphasizing the importance of molecular packing and film morphology in optimizing device performance. [ABSTRACT FROM AUTHOR]

• S.A. Sharko, A.I. Serokurova, N.N. Novitskii, V.A. Ketsko, A.I. Stognij. • Nanosized bulk-like nickel films were obtained by ion-beam sputtering – deposition. • Granulation suppression at early formation stage ensures layer-by-layer film growth. • Ni films after ten cycles 'deposition – partial sputtering' are more homogeneous. • The root-mean-square roughness of metal films decreases to a level of less than 1 nm. Thin nickel films up to 50 nm thick with bulk-like properties were obtained on quartz and silicon substrates with the ion-beam method by tenfold applying the 'deposition – partial sputtering of a nanosized metal layer' cycle. The use of this technique ensures layer-by-layer film growth due to both the granulation suppression at the early stage of formation through the influence of high-energy metal atoms during film deposition, and argon ions during its partial sputtering. This creates conditions for the strong adhesion of the metal layer to the substrate and, therefore, leads to the growth of continuous nickel films with a high degree of homogeneity. Transition from single to multiple deposition causes a decrease in the root-mean-square roughness of the film surface, as well as an improvement in the thermal stability of the film/substrate structure. The results of optical studies show that the films become more optically homogeneous. The decisive role in their formation is played by the elastic collision of incident metal atoms with stationary atoms of the substrate and the growing metal film. [ABSTRACT FROM AUTHOR]

• Effects of the x on the surface roughness of Cu2Sn1-xGexS3 (CTGS) films were examined. • The increased surface roughness is caused by re-evaporation of GeS and large grain. • Suppression of forming of Ge2SnS3 and CGS, and deposition of lower x-CTGS are needed. The effects of the [Ge]/([Ge]+[Sn]): x ratio on the increase in the surface roughness and growth mechanism of Cu 2 Sn 1- x Ge x S 3 (CTGS) films were examined as a first step toward realizing high-efficiency CTGS solar cells. The surface roughness of the CTGS films did not change significantly up to 450 °C during the sulfurization of the Ge/Cu/SnS precursors, whereas that of the CTGS films increased beyond 500 °C. Further, Cu 2 GeS 3 (CGS) and germanium sulfide (GeS) were observed via X-ray diffraction; these CGS and GeS compounds remained in the upper layer up to 540 °C, and CTGS was formed at 560 °C by the reaction with Cu 2 SnS 3. The increased surface roughness in the CTGS films is attributed to the larger CTGS grain size that increases the x ratios of CTGS and the re-evaporation of vapor atoms (e.g., GeS) that generates a high vapor pressure on the surface of films by forming CGS and GeS compounds. These results confirm that the formation of CGS and GeS compounds, and the formation of dense grains in the CTGS films caused by the deposition of lower x ratios in the CTGS films are effective measures for improving the overall surface roughness. [ABSTRACT FROM AUTHOR]

• Highly transparent and nearly superhydrophobic surface can be achieved. • The relationship between optical transmittance and etching depth was studied. • Surface roughness-dependent water contact angle and sliding angle were studied. Highly transparent, superhydrophobic coatings are highly desirable for maintaining long-lasting clarity for outdoor camera windows. In this study, the authors present a simple approach to create a wide–range anti-reflective and highly hydrophobic layer on a glass surface. This is accomplished through a hydrothermal alkali etching process combined with a dip-coating process using 1 H, 1 H, 2 H, 2 H-Perfluorooctyltrimethoxysilane (POTS). The sample, etched for 20 h and modified by POTS, exhibiting an average transmittance of 96.5 %, a water contact angle (WCA) of 140° and a sliding angle (SA) of 40°. The results of the water spray experiment indicate this surface exhibits excellent water repellent performance, preventing water droplets larger than 0.01 mm in size. The relationship between optical transmittance and etching depth was thoroughly studied, revealing that an etched depth ranging from 200 nm to 600 nm yields optimal wide-spectrum anti-reflective properties. Furthermore, the influence of surface roughness on apparent WCA and SA was investigated. It was found that root mean square (RMS) roughness can be an effective factor to predict the apparent WCA of a surface, while both the RMS roughness and morphological structure affect the SA. [ABSTRACT FROM AUTHOR]

• ZnQ 2 powder stability is assessed with a DSC thermogram. • Vacuum thermal evaporation is employed for fabricating ZnQ 2 thin films. • Annealing changed the morphology and structure of the films. • ZnQ 2 films are optically and structurally stable up to 373 K. • ZnQ 2 can be used for both IR and UV optical switching. In this study, the effect of thermal annealing on the structural and optical properties of thermally evaporated zinc (8-hydroxyquinoline) (ZnQ 2) thin films is discussed in detail. Differential scanning calorimetry analysis revealed the thermal stability of the ZnQ 2 powder up to 540 K. Fourier transform infrared spectrometer characterizations revealed the stability of the ZnQ 2 molecular structure up to 423 K. The annealing effect on the surface morphology of the ZnQ 2 films was tracked using the field emission scanning electron microscope (FE-SEM) technique, which revealed grain growth up to 423 K achieving the highest surface smoothness. Moreover, UV–Vis-NIR spectrophotometric measurements were used to examine how annealing affects the optical characteristics of the prepared films. The optical bandgap of ZnQ 2 augmented when the annealing temperature increased to 373 K. The dispersion parameters were estimated from the analysis of the complex refractive index following the single oscillator model. The behavior of nonlinear optical susceptibility suggested the validity of utilizing ZnQ 2 thin films in IR and UV optical switching applications and UV photodetection applications. [ABSTRACT FROM AUTHOR]

Wurtzite zinc oxide (ZnO) has a preferential growth direction along the c -axis of the hexagonal unit cell, which, especially in combination with underlying (amorphous) heterostructures, can lead to a high surface roughness for the ZnO layers. This poses a significant challenge to the construction of e.g. photonic waveguides or gratings. Here, we propose an efficient way for smoothing ZnO surfaces after deposition using a collimated beam of Argon ions. Furthermore, the influence of this treatment at different angles of incidence and fluence of the ions on the morphological, structural and linear optical emission properties is investigated using atomic force microscopy, X-ray diffraction, spectroscopic ellipsometry and photoluminescence (PL) experiments. Our results suggest that using an ion beam incident at an angle of 85 ° reduces the surface roughness by around 70% while keeping the ZnO crystal structure intact. Though such a treatment leads to a reduced intensity and to a broadening of the PL-emission, excitonic transitions are still prominently observable. • Ion beam assisted direct smoothing of ZnO surfaces of distributed Bragg reflector. • X-ray Diffraction revealed intact wurtzite structure with reduced quality. • Reduction of the surface roughness by more than 70%. • Smoothing occurs across a broad range of spatial wavelengths. • Optimum conditions found for smooth surface while maintaining optical properties. [ABSTRACT FROM AUTHOR]

The all-inorganic perovskite material (CsPbBr 3) is a promising light-emitting material due to its narrow color spectrum, wet solution processability, and cost-effectiveness. Despite such advantages, pinholes, poor surface coverage, and stability issues limit widespread applications of perovskite light-emitting devices (PeLEDs) in solid-state lighting applications. The performance of PeLEDs depends strongly on the morphological characteristics of the perovskite layer, with low surface coverage and surface roughness observed to lead to higher current leakage and lower current efficiency. We find that perovskite thin films blended with polymers to form composite layers effectively enhance the thin film's surface coverage and uniformity, improving performance. We report CsPbBr 3 PeLEDs with dual polymer additives, with a 12.1% reduction in the turn-on voltage (V on), a 97.21% reduction in leakage current density, a 200%+ enhancement in maximum brightness, and a 700% increase in power efficiency compared to a control CsPbBr 3 device. To study the likely source of these enhancements, we have conducted a comparative film analysis of test and control devices using field-emission scanning electron microscopy and atomic force microscopy. A reduced crystal grain size (∼ 204 nm to ∼ 101 nm) and a nearly 100% (99.79%) surface coverage (compared to 79.53% found for control devices) suggest that the improved overall morphology and surface coverage likely play a significant role in the improved performance. Further, a reduction in surface roughness (∼ 45%) and the formation of a nearly pinhole-free film are observed to increase yield by 20%. • Enhanced surface coverage and improved grain size uniformity. • Perovskite-polymer blended light emitting diodes. • Reduction of non-radiative loss pathways. [ABSTRACT FROM AUTHOR]

Silver nanowires (AgNWs) based conductive electrode have shown potential for use in large area flexible optoelectronic applications. Presently, considerable efforts are being made to lower the surface roughness and enhance the opto-electrical performance of AgNWs based transparent conductive electrode(TCE) for optoelectronic application, which require a smooth surface for high efficiency performance. In this work, we designed a hybrid metal electrode with low surface roughness fabricated by coating an AgNWs onto a metal mesh on Polyethylene terephthalate substrate (AgNW/MM/PET). The AgNW/MM/PET TCE, fabricated by a method of hot pressing after wire wound-rod coating process, exhibits a low surface roughness of 8 nm and 16.33 nm of maximum peak-to-valley value with the low sheet resistance of 0.668 Ω/sq. and a high optical transmittance of 91.25% at λ = 550 nm. In addition, the hot pressed AgNW/MM/PET TCE shows excellent mechanical stability along with long-term reliability in bending tests and strong adhesion in taping test, compared to the annealed AgNW/MM/PET TCE. Therefore, the hot pressed AgNW/MM/PET electrodes with low surface roughness and high opto-electrical performance could be a potential candidate to replace indium doped tin oxide electrodes in flexible electronic application. • Hot pressed Silver nanowire (AgNW) on Metal mesh (MM) electrode was prepared. • Hot pressed AgNW/MM/PET electrode exhibited low surface roughness of 8 nm. • Hot pressed AgNW/MM/PET exhibits 0.668 Ω/sq. with 91.25% of transmittance. • Hot pressed AgNW/MM/PET electrode was reliable in bending and taping test. [ABSTRACT FROM AUTHOR]

Electric field assisted dissolution is a process that enables micro- and nano- structuring of metal nanocomposite glasses, metal island films and compact metal layers on glass substrates, using simple equipment and technical setup. During the process, metal ions drift into a glass matrix under the influence of moderately elevated temperature and the applied electric field. The surface quality of nanostructured metal layers has great importance in many applications as it influences the device performance. In this work, a study of the surface morphology evolution during the dissolution of a compact metal layer is presented. It is found that in the course of gradual change from a compact to a completely dissolved layer, drift of metal ion s from glass/layer interface is followed by the simultaneous deterioration of the surface quality already from the very beginning of the process. The surface morphology evolution could be described by the occurrence of surface roughness of the metal layer and continuous thinning of the layer. Understanding how this process takes place is important for improvement of electric field assisted dissolution application in structuring metal layers for optoelectronic devices. • Ag film surface evolution upon electric field assisted dissolution is studied. • Compact film shows widening channels and film thinning prior complete dissolution. • In regions with no direct contact with electrode, film dissolution is slower. • Surface morphology transition is well-correlated with change of dielectric function. [ABSTRACT FROM AUTHOR]

Biosensor development has relied on the process of anodization of sputtered aluminum‑tantalum thin films to develop specific optical properties for interference color generation. The anodization of thin sputtered films of aluminum (140 nm) on tantalum (230 nm) on silicon was completed in 0.4 M phosphoric acid under potentiostatic conditions (4 V) and with various additives: 0.1 M and 0.4 M citric acid, 3% (v /v) and 10% (v/v) of a commercial anodizing solution consisting of glycerol and glycolic acid, and 0.1 M and 0.4 M oxalic acid. The microstructural and optical properties of these films were analyzed using scanning electron microscopy, X-ray diffraction, and ellipsometry. The interference colors produced by the anodic aluminum and tantalum oxides on top of the tantalum metal layer were also observed. The addition of 0.1 M citric acid, 3% (v /v) glycerol and glycolic acid-based solution, and 0.1 or 0.4 M oxalic acid all produced changes to the porous microstructure of the anodic alumina, including lower roughness and more homogeneous surfaces by inhibition of the dissolution from phosphoric acid. Oxalic acid acted as the strongest inhibitor and significantly reduced surface roughness and pore size, increased the composite refractive index of the anodized film, and significantly changed the interference colors compared to films where no additive was used. • Porous anodization of Al Ta thin films is important in the field of biosensors. • Tailored thin film optical properties allow development of Al 2 O 3 -Ta 2 O 5 diagnostics. • Additives to a H 3 PO 4 anodization bath improve microstructure and optical properties. [ABSTRACT FROM AUTHOR]

The development of nano-structured mixed-phase titania thin films and the relationship to photocatalytic activity (PCA) is of interest for pollution reduction and antimicrobial applications. A set of films grown by pulsed pressure metallorganic chemical vapour deposition using titanium tetraisopropoxide precursor was studied. The growth method is single-stage, scalable and produces high-quality, adherent films. Film thicknesses were 101 nm to 4.0 μ m. Three growth stages were identified. All films were a mixture of anatase and rutile. Early stage films had rounded morphologies, low surface roughness and low PCA. Transition stage films developed columnar [110] orientated anatase dendrites, contained amorphous carbon and had reduced UV transmittance. Late stage films had strong anatase (220) and rutile (200) textures, contained amorphous carbon and exhibited highly branched anatase dendrites with nanoscale secondary plates. PCA was determined from degradation of stearic acid and correlated with increasing surface roughness. The most active film had formal quantum efficiency of (6.62 ± 0.64) × 10−4 molecules/photon, 59 times higher than a commercially available control. The performance is attributed to the combination of phases yielding polymorphic phase boundaries and amorphous carbon enhancing the adsorption of organic molecules, the unusual (220) anatase texture yielding nanostructured anatase dendrites in combination with nanocrystalline rutile and hierarchical porosity. • Films of textured titania with amorphous carbon on fused silica • Grown by pulsed pressure metallorganic chemical vapour deposition • Simple, scalable method gives nanostructured films with hierarchical porosity • Highest photocatalytic activity (PCA) obtained with highest surface roughness • Nanoscale plates, mixed phases, and increased organic adsorption maximize PCA [ABSTRACT FROM AUTHOR]

Sn Cu alloy electrodeposits have found a wide range of applications in the electronics, automotive and aerospace industries. In the current research, the electrodeposition of Sn Cu alloy coatings produced from an electrolyte based on fluoroboric acids was thoroughly studied. The cathode current density was found to have a significant impact on the appearance and the surface morphology of Sn Cu alloy electrodeposits. Our experimental results suggested that deposition current density, magnetic agitation and pulsed current parameters (pulse frequency and duty cycle) were all found to be crucial factors significantly affecting the chemical composition of the Sn Cu alloy electrodeposits. In addition, the employment of pulsed current techniques significantly improved the edge effect and the surface roughness. Whisker growth on the Sn Cu alloy electrodeposits was assessed. All the samples subjected to different electroplating condition were prone to develop Sn whiskers after a few weeks of storage at room temperature. • Deposition current density affects the appearance and the surface morphology. • Magnetic agitation and pulsed currents favour co-electrodeposition of copper. • Pulsed current electroplating improves surface roughness and edge effect. • Tin-copper alloy electrodeposits are prone to develop tin whiskers. [ABSTRACT FROM AUTHOR]

Antiphase boundaries in spinel ferrites have been considered as the functional elements with great potential for applications in spintronic devices. Engineering the antiphase boundaries is a big challenge in experiments. Here, we report on that a high density of antiphase boundaries in CuFe 2 O 4 films have been prepared on rough surface of MgAl 2 O 4 (001) substrates. By means of advanced electron microscopy these antiphase boundaries are found to be of {011} 1 4 〈011〉-type and bound by interfacial dislocations with Burgers vector of a /4〈011〉 that contribute to relaxation of in-plane and out-of-plane lattice strain in the heterostructure. Our results provide evidence that the rough substrate surface can be applied for the formation of antiphase boundaries in the CuFe 2 O 4 /MgAl 2 O 4 system to tune the magnetic and electrical transport properties of epitaxial spinel ferrite films. • Antiphase boundaries form in the spinel CuFe 2 O 4 films on rough MgAl 2 O 4 (001) substrates • The {011} 1 4 〈011〉-type antiphase boundaries are bound by a /4〈011〉-type misfit dislocations. • Antiphase boundaries release the epitaxial strain in the CuFe 2 O 4 /MgAl 2 O 4 heterostructures. [ABSTRACT FROM AUTHOR]

Abstract A phenomenological model has been developed and discussed. The model is able to describe the experimentally measured light transmission of nanowires arrays. Two representative samples were studied in this report. A well aligned nanowires sample was first modelled by an effective layer model with surface roughness added. Then a slightly tilted nanowires sample with round top was phenomenologically modelled by a two layers model with a first top layer of an effective medium which includes a volume scattering contribution (Mie theory). Roughness and waviness are added to account for the nanowires small and large scale fluctuation in height. This phenomenological description was proven to be feasible by fitting experimental data. As a conclusion, light transmitted through randomly distributed nanowires can be explained by the combination of volume and surface scatterings using respectively Mie theory and rough Fresnel coefficients at the interfaces. Highlights • Simulation of light transmission through randomly distributed nanowires arrays. • Mie contribution is accounted for the extinction coefficient of the thin film. • Retrieved parameters are comparable to the real geometry. [ABSTRACT FROM AUTHOR]

Abstract In this study, the effect of NH 3 pre-treatment is investigated to obtain high-quality nitrogen-polar GaN grown on a SiC substrate. The GaN/AlN/C-face 4° off-cut SiC structure is successfully grown with pre-treatment temperatures of 1250, 1300, and 1350 °C. The hillock and inversion domain density, surface roughness, and crystal quality of each sample were evaluated. As the temperature increased from 1250 °C to 1350 °C, the overall crystal quality of the N-polar GaN was greatly improved with reduced hillock and inversion domain densities and smoothed surface. The X-ray rocking curve full-width at half maximum of the (00-2) and (10-2) planes were 374 and 420 arcsec, respectively, for the pre-treatment of 1350 °C. Highlights • Effect of ammonia pre-treatment temperature on N-polar GaN growth was reported. • As pre-treatment temperature increased, N-polar GaN quality was improved. • Best N-polar GaN quality was shown at 1350 °C pre-treatment. • Hillock and inversion domain densities were decreased. • Surface roughness decreased, and crystal quality was improved. [ABSTRACT FROM AUTHOR]

Abstract As a follow up on a previous paper on the quantitative evaluation of sputtering induced surface roughness and its influence on Auger electron spectroscopy depth profiling of polycrystalline Ni/Cu multilayers thin films, the ion sputtering induced surface roughness of these multilayered Ni/Cu polycrystalline thin films under low energy (0.5, 1.0 and 2.0 keV) O 2 + ion bombardment and 1.0 keV Cs+ ion sputtering were investigated with Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Atomic Force Microscopy (AFM). The lowest energy (0.5 keV) O 2 + ion sputtering gave the best depth resolution for the different energy ion sputtering. Furthermore the 1.0 keV Cs+ ion sputtering led to a better resolution than the O 2 + ion sputtering. The ToF-SIMS depth resolution was also better than the AES depth profiling with a 2.0 keV Ar+ ion sputtering. The Mixing-Roughness-Information depth (MRI) model used for fitting of the ToF-SIMS depth profiles accounts for the broadening upon experimental depth profiling owing to the effects of atomic mixing, surface roughness and information depth. The MRI fitted roughness parameters obtained from the ToF-SIMS depth profiling are in good agreement with the root-mean-square roughness obtained from the AFM topography scans of the crater bottom. Ion sputtering induced roughness and depth resolution during ToF-SIMS depth profiling of Ni/Cu multilayers were quantitatively evaluated according to the MRI fitting parameters. Highlights • Depth profiles with Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). • Depth-dependent ion sputtering induced roughness of the Ni/Cu multilayers. • Low energy O 2 + ion bombardment effects with ToF-SIMS. • Quantitatively analysed by the Mixing-Roughness-Information depth (MRI) model. • MRI fitted roughness parameters compared well with roughness values. [ABSTRACT FROM AUTHOR]

• TiSiN films were deposited by magnetron sputtering method. • TiSiN films were deposited on 52100 steel and Al2024 substrates. • The film thickness increased depending on the si content. • The highest hardness value for TiSiN films were 6.06 GPa. • The lowest wear rate was 1.63 × 10−4 mm3/(N.m). TiSiN thin films were deposited on 52100 steel and Al2024 substrates by magnetron sputtering method using Ti and Si targets in Ar+N 2 atmosphere. Power values of 40 W, 60 W, and 75 W were applied to the Si target, while the voltage was constant at 370 V for the Ti target. The Si atomic ratios within the film's structure were found to vary in accordance with the increasing Si target power. The impact of varying Si atomic ratios on the structural, mechanical, and tribological properties of the films was investigated. X-ray diffraction, scanning electron microscopy, hardness and wear test methods were performed. As the Si ratio increased from 10 at. % to 20 at. %, the maximum hardness value was 6.06 GPa for 52100 steel and 4.33 GPa for Al2024. With increasing Si content, the film thickness increased from 1.63 µm to 2.05 µm. The lowest surface roughness of the produced films was 0.069 for 52100 steel and 0.308 for Al2024. The lowest wear rate of TiSiN film was calculated at 1.63 × 10−4 mm3/(N.m). [ABSTRACT FROM AUTHOR]

• A super-hydrophobic, electromagnetic shielding titanium nitride film is prepared. • Increasing the sputtering power can construct a low energy, high roughness surface. • Increasing the sputtering power will improve the electromagnetic shielding effectiveness. • Film with 151.3 °contact angle and 40 dB shielding effectiveness is obtained. A super-hydrophobic, electromagnetic shielding titanium nitride (TiN) film was prepared using reactive magnetron sputtering by adjusting the sputtering power (30, 90, 180 and 250 W). The results showed that preferred orientation of the film had an obvious change with increasing sputtering power. At 30 W, too low sputtering power was not conducive to the crystallization of the film. At 90 W, TiN film grew toward [200] preferred orientation with a flat and compact surface, while the preferred orientation was [111] at 180 and 250 W with an uneven surface. Higher sputtering power could construct a low energy and high roughness surface which was helpful to improve the hydrophobic property. The water contact angle of the as-prepared TiN film at 250 W was 151.3°, indicating the achievement of super-hydrophobic property. Due to the decrease of electrical resistivity, the increase of film thickness and the special microstructure of pyramidal nanoparticles, the electromagnetic shielding effectiveness of TiN film at sputtering power of 250 W was about 40 dB, meaning that TiN film had good expect to be a super-hydrophobic, electromagnetic shielding material in the industrial field. [ABSTRACT FROM AUTHOR]

Combining chemical vapor deposition (CVD) with electrochemical polish (EP) operation is a promising route to producing performance-capable superconducting films for use in the fabrication of cost-effective components for superconducting radiofrequency (SRF) particle accelerators and superconducting quantum computers. The post-deposition EP process enables a critically necessary reduction in surface roughness of niobium (Nb) thin films to promote optimal superconducting surface conditions. This work investigated surface morphology, roughness, and crystal orientation of the CVD-grown and EP-polished Nb films. The CVD films were found to comprise steps and pyramidal features, resulting in undesirable large peak-to-valley distances. EP was demonstrated to significantly diminish the height of pyramids and effectively minimize the overall surface roughness. EP results showed a probable dependence on the crystal orientation. These understandings identify the EP principles tied to CVD-grown Nb films that allow further refinement of surface profiles for film-based SRF applications. • Chemical-vapor-deposited (CVD) niobium films show large steps and pyramidal features. • Electropolishing (EP) reduces large surface roughness on CVD niobium films. • EP of CVD niobium films involves both macroscale and microscale smoothing. • The film EP results suggest a probable crystal orientation dependence. • Combining EP-CVD makes film-niobium feasible for superconducting radiofrequency use. [ABSTRACT FROM AUTHOR]

• Tuning of Al content in ZnO thin films by confocal RF magnetron co-sputtering. • Effects of Al content and annealing on the optoelectronics properties of AZO films. • The chemical results have revealed the incorporation of Al in the ZnO matrix. • Diffraction results revealed that the film's crystallinity is affected by Al doping. • High figure of merit was obtained for the film with aluminum content of 3.6 at.%. Al-doped ZnO thin films with varying Aluminium (Al) content were deposited by radio frequency magnetron co-sputtering of two ZnO and Al targets in confocal configuration. A comprehensive study of the effect of Al content variation on the structural, optical and electrical properties were studied for as-deposited films and after an annealing step under controlled argon atmosphere. Chemical composition analyses, performed by both X-ray photoelectron spectroscopy and energy dispersive X-ray spectrometry, show an Al content variation in the deposited films in the 0-14 at.% range by varying the Al target power from 0 to 30 W, while the Zn target power was kept constant at 200 W. All deposited films exhibit a wurtzite crystalline structure and a decreasing crystalline quality for Al content above 5 at.% as shown by grazing incidence X-ray diffraction patterns. Atomic Force Microscopy analysis revealed films with homogeneous and dense surface morphology with roughness in the one nm range. Carrier concentration, resistivity and photoluminescence vary significantly with Al content in the ZnO films and appear optimized for an Al content window ranging from 1.5 to 5.5 at. %. Both optical and electrical properties are improved by a post-annealing at 300°C under argon. A high figure of merit of 43.6 × 10-4 sq.Ω-1 was obtained for the ZnO film with Al content of 3.6 at.% after annealing at 300°C. Optimized properties are obtained for a higher Al content than the standard value of 2 at. % widely used in published works. [ABSTRACT FROM AUTHOR]

Abstract Molybdenum (Mo) thin films are widely used in microelectromechanical systems (MEMS) applications. Mo bilayer deposition by direct current (DC) magnetron sputtering has been proposed in order to attain the desired smooth surface, small in-plane tensile stress and high degree crystallisation of Mo thin film for the fabrication of MEMS actuators and electrodes. The influences of sputtering time (10 min–40 min) and sputtering DC power (100 W–250 W) on the physical and microstructural properties of single layer Mo thin film have been evaluated. The optimised sputtering conditions for bottom and top layer of Mo bilayer have been determined and the individual influence of each layer on the resulting Mo bilayer has been discussed. Our studies reveal that the deposition of top Mo layer with small surface roughness but high in-plane tensile stress has reduced the high surface roughness of bottom Mo layer and simultaneously retained the small in-plane tensile stress. Reducing the sputtering time and/or using similar sputtering power for bottom and top layers improved the crystallinity of Mo bilayer along the preferred 〈110〉 direction. Mo bilayer thin films of total thickness < 1 μm, crystallite size >19 nm, surface roughness <2.5 nm and in-plane tensile stress <500 MPa have been attained. Highlights • Reduce molybdenum (Mo) surface roughness, R a by depositing top Mo layer of smaller R a. • Similar sputtering power for top and bottom layer yields good crystals in Mo bilayer. • Strong association between tensile stress and compressive strain in Mo mono/bilayer. [ABSTRACT FROM AUTHOR]

Iridium layers with low stress, high density, and low surface roughness find widespread use in different high-technology applications. This paper presents a study of the influence of the sputtering pressure on the properties of iridium thin films and of its effect on the substrate surface microstructure. We analysed the dependence of the microstructure, crystalline structure, electrical resistivity, and deposition rate on the sputtering pressure and surface defects of the substrate. For the latter, plasma etching of the substrate was performed for different processing times and its effect on the surface roughness of substrates and, subsequently, on the grown iridium films, was examined. The sputtering pressure and the substrate plasma etching time both had a strong influence on the microstructure and surface roughness. These microstructural changes are in good agreement with the tendency described in the Thornton Structure-Zone Model for different sputtering pressures and the microstructure phase map of Alvarez. The electrical resistivity, deposition rate, and crystalline structure were highly dependent on the sputtering pressure. [ABSTRACT FROM AUTHOR]

Silicon oxide films were deposited on glass and polyethylene terephthalate (PET) substrates by means of radio-frequency (RF) magnetron sputtering and the effects of the RF power on the microstructure, morphology, composition and wetting property of the films were investigated and compared. It was found that the films on PET have more voids and fissures than those on glass, especially those deposited with a RF power lower than 200 W, while the films on glass are all compact. All films possess the columnar structure and columns in the films on PET are coarser. These differences are supposed to result from the slower nucleation and faster diffusion on PET. Higher RF power provides particles with higher kinetic energy and produces films with denser structure and coarser columns. The silicon oxide films on both kinds of substrate have comparable thicknesses and compositions with an O/Si atomic ratio of 1.5. The surface roughness of the films is contributed from the roughness of substrate and the true roughness of films and the true roughness of films on both kinds of substrates reaches minimum at 200 W. The contact angle of water on the films shows a similar tendency, while the contact angle on PET is found lower than that on glass. The mechanism which explains the void formation of the film on PET can rationalize the difference. [ABSTRACT FROM AUTHOR]

A comparative study has been carried out on microstructural evolution, surface roughness, nanoindentation and scratch behavior, electrical resistivity, and corrosion resistance of Ni 1-x Zr x (0.13 ≤ x ≤ 0.40) thin films deposited on Si-(100) substrate by DC magnetron co-sputtering of high purity elemental targets in argon atmosphere. The film compositions have been examined by energy dispersive X-ray and Auger electron spectroscopy. Grazing incidence X-ray diffraction (GIXRD) studies have shown presence of Ni-rich solid solution, Ni 3 Zr and amorphous phase in all the films, with Ni 5 Zr being additionally observed in the Ni 87 Zr 13 film. Analysis of GIXRD data along with transmission electron microscopic studies have shown that volume fractions of both amorphous phase and Ni 3 Zr are increased, whereas the average crystallite size is decreased with increase in Zr concentration. Nanoindentation hardness and Young's modulus as well as electrical resistivity measured by Van-der Pauw four-probe method are influenced by volume fractions of both Ni 3 Zr and amorphous phase. Surface roughness and coefficient of friction obtained from atomic force microscopy and nano-scratch experiments, respectively decrease, whereas corrosion resistance in 3.5 wt% NaCl solution increase with Zr concentration primarily due to increase in amorphous phase content. Resistance to pitting corrosion is facilitated by formation of ZrO 2 -rich passive film, as confirmed by X-ray photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

To produce hydrogenated amorphous carbon (a-C:H) films with high mass density at a high deposition rate and low substrate bias voltage, we deposited these films on a Si substrate by plasma chemical vapor deposition, using toluene as a source compound and varying the gas flow-rate ratio of H 2 /(H 2  + Ar). By decreasing the gas flow-rate ratio from 55% to 11%, the hydrogen content in the films decreased, and the density of sp 3 carbon atoms in the films increased, whereas their surface roughness increased. At the gas flow-rate ratio of 11%, we produced a-C:H films with a high bulk density of 1830 kg/m 3 at a high deposition rate of 81.1 nm/min. [ABSTRACT FROM AUTHOR]

Germanium, copper and silver(I) oxide seed layers are investigated for their ability to reduce the roughness of silver thin films deposited on amorphous substrates. Such films are useful in disease detection and sub-wavelength imaging applications, provided their surface roughness is sufficiently low so as to give a strong plasmonic response. Surface roughness and optical transmission measurements are reported for thermally evaporated and radio frequency sputtered silver films between 10–40 nm thick, grown either directly on amorphous borosilicate glass substrates or on top of 1 nm thick seed layers. It is found that germanium, copper and silver(I) oxide seed layers all have a smoothing effect on silver films up to 20 nm thickness. In the best case, the root means square surface roughness of a 10 nm silver film thermally evaporated onto borosilicate glass was reduced from 2.16 ± 0.16 nm to 0.71 ± 0.04 nm by the inclusion of a 1 nm thick germanium seed layer. For films thicker than 20 nm only germanium had a significant smoothing effect. The effects of thermal annealing on the surface roughness and optical transmission of silver films grown on the various seed layers were also investigated. The optical transmission over ultraviolet and visible wavelengths was increased and the surface roughness was decreased for films grown on a germanium seed layer, but the reverse was observed for films grown on the copper or silver(I) oxide seed layers or on the bare substrate. The silver films degraded during annealing due to dewetting, which occurred at a threshold temperature determined by the seed layer or substrate. These experiments pave a pathway towards extremely smooth, low-loss silver films at arbitrary thicknesses. Results support the development of more sensitive, robust, and reliable plasmonic devices for medical diagnosis, imaging, and particle sensing. [ABSTRACT FROM AUTHOR]

Photoluminescence (PL) emission properties of Bi-doped Y 2 O 3 (Bi:Y 2 O 3 ) phosphor thin films were investigated depending on the oxygen content in the sputtering atmosphere to find out the optimal oxygen content for obtaining Bi:Y 2 O 3 phosphor thin film with strong PL emission intensity. PL emission intensity was greatly increased by adding a small amount of oxygen to the sputtering atmosphere. However, it was gradually decreased with further increasing the oxygen content. This behavior is thought to be due to the variation of crystallinity and surface roughness of the film depending on the oxygen content in the sputtering atmosphere. The film crystallinity showed similar behavior to PL emission intensity and the surface roughness except the case of Ar only was also decreased gradually with increasing the oxygen content. Density of point defects such as oxygen vacancy and interstitial in the film was expected to be changed according to the oxygen content in the sputtering atmosphere and also this change was considered to have an effect on the PL emission intensity of the Bi:Y 2 O 3 film. In this work, Bi:Y 2 O 3 phosphor thin film with the strongest PL emission intensity could be fabricated with the oxygen content of 10% in the sputtering atmosphere. [ABSTRACT FROM AUTHOR]

In this method, CuGaO 2 thin films were prepared by a sputtering method and annealing treatment under a controlled nitrogen atmosphere to investigate the relationship between the structural changes and optoelectronic properties of Cu–Ga–O thin films. The amorphous Cu–Ga–O thin films exhibited a low surface roughness, high resistance, and a high photon absorption capacity. The thin film with composite phases of CuO, CuGa 2 O 4 , and CuGaO 2 structures did not exhibit dominant absorption characteristics at a specific wavelength; the bandgap of the material was 2.44 eV, making it a high-resistance thin film. The formation temperature of single-phase CuGaO 2 was 750 °C. CuGa 2 O 4 and CuO reacted to form CuGaO 2 . CuGaO 2 exhibited a high-temperature phase, and a polygon-like microstructure was observed in the thin-film cross section. With increasing annealing temperature, the surface roughness, average grain size, direct bandgap, and resistivity of the CuGaO 2 thin films increased accordingly. The surface roughness of the CuGaO 2 thin films ranged from 5.7 nm to 7.3 nm, with average grain sizes ranging from 35.5 nm to 39.0 nm. The direct band gaps of CuGaO 2 annealed at 750 °C, 800 °C, 850 °C, and 900 °C were 3.45 eV, 3.50 eV, 3.64 eV, and 3.65 eV, respectively; their corresponding resistivities were 57.4 Ω cm, 78.9 Ω cm, and 121.7 Ω cm, respectively. At a higher annealing temperature (900 °C), the thin film was unable to retain single- phase CuGaO 2 , instead forming a secondary phase of GaO. [ABSTRACT FROM AUTHOR]

Antiphase boundaries free GaSb epitaxial layers with low surface roughness (< 0.5 nm) have been synthesized on standard microelectronic 300 mm nominal (001)-Si substrates by metal organic chemical vapor deposition using a two-step growth process. By adjusting the growth temperature and the thickness of the nucleation layer, antiphase boundary free GaSb layers as thin as 250 nm are obtained. The 12% lattice mismatch between GaSb and Si is accommodated by both the formation of threading dislocations and a periodic array of 90° misfit dislocations at the interface. A GaSb layer inserted between AlSb barriers has been grown on an optimized GaSb/(001)-Si buffer layer and exhibits room temperature photoluminescence. [ABSTRACT FROM AUTHOR]

• Successful fabrication of superhydrophobic Ni-Zn electrodeposited coatings. • Employing power spectral density (PSD) analysis to describe hierarchical structures. • Linking the wettability of coatings to PSD parameters to establish a relationship. • Introducing superhydrophobicity index to predict wettability behavior of surfaces. This paper aims to establish a quantitative relationship between wettability and surface morphology. The wettability of surfaces is highly dependent on surface morphology, and this relationship will be explored using either conventional roughness parameters or power spectral density (PSD) derived parameters. To investigate the effect of surface morphology on wettability, various Ni-Zn coatings with different hierarchical surface morphologies were electrodeposited on copper substrates. The coatings exhibited hydrophobic behavior with apparent contact angles ranging from 105° to 155°, depending on the shape, size, and arrangement of their surface features. Although conventional roughness parameters like S q and S pc influenced the wettability of the coatings, their absolute values could not accurately predict superhydrophobic behavior. Therefore, the PSD analysis was used as an alternative approach to predict the wettability behavior of the coatings by distinguishing between nano- and micro-features. The results revealed that a superhydrophobicity (SH) index could be obtained from the PSD model to predict superhydrophobic properties. Coatings with an SH index below 0.32 exhibited a contact angle greater than 150°, regardless of their deposition parameters. The findings suggest that surface roughness plays a significant role in controlling the wettability of Ni-Zn coatings, and the SH index is a useful tool for predicting the superhydrophobic properties of these coatings. [ABSTRACT FROM AUTHOR]

• Fabrication of thin film LaFeO 3 photocathode via spray gun deposition is proposed. • The high surface roughness results in optical function improvement towards visible light response. • Photocurrent density enhances almost double as surface recombination is suppressed. • Photoelectrochemical performance exhibits a stable operation in strong alkaline media. To date, numerous methods have been employed in fabricating lanthanum iron oxide (LaFeO 3) photocathodes. However, producing practical and stable single thin film LaFeO 3 photocathodes for photoelectrochemical (PEC) operation remains a challenge as the photocurrent produced is too low. In the present work, LaFeO 3 photocathodes were fabricated via spin coating and spray deposition using an inexpensive commercialized disinfectant spray gun. The study discovered that applying the spray gun deposition onto the spin-coated layer resulted in enhanced LaFeO 3 micro-structural formation with a high degree of surface roughness. The visible light absorption improved with the energy band gap reduced from (2.45 ± 0.1) eV to (2.42 ± 0.1) eV due to the enhancement of morphological formation. Furthermore, the PEC performance showed a good photocathodic response with the photocurrent density increased from 15.2 μA cm−2 to 27.0 μA cm−2 at 0.6 V (vs. Ag/AgCl), resulting in good charge transfer behavior and stability in the strong alkaline solution. Therefore, the LaFeO 3 thin film fabricated in this study could provide valuable information, hence, would be reliable to apply on scalable optoelectronic device production particularly the PEC photocathodes with simple processes and low-cost equipment. [ABSTRACT FROM AUTHOR]

• LaxCa0.89-xSr0.11MnO3 films were prepared by sol-gel spin coating method. • Film exhibited temperature coefficient of resistivity (TCR) of 8.8%/K at 283.2 K. • La3+ doping is helpful to control peak TCR temperature at room temperature. • Films displayed smooth and uniform surface with average roughness of 1–4 nm. • The results are beneficial for uncooling infrared bolometer application. Herein, refined La x Ca 0.89- x Sr 0.11 MnO 3 (LCSMO, x = 0.65, 0.68, 0.71 and 0.74) films were prepared through the sol-gel spin-coating. The influence of La3+ content on the structural properties of LCSMO films was investigated by X-ray diffraction and Atomic force microscope, demonstrating that LCSMO films can grow well on SrTiO 3 (00 l) substrate. Besides, X-ray photoemission spectroscopy verified the double exchange (DE) effect was weakened with La3+ dopant. The La3+ doping and interconnected grains boundaries (GBs) led to the weakening DE effect and GBs scattering, respectively. Due to superior GBs connectivity, the resistivity of LCSMO films was less than 7.1 × 10−4 Ω·cm at low temperature of 100 K. Importantly, it is an effective control method to keep the temperature (T k) corresponding to temperature coefficient of resistivity (TCR) at room temperature with Sr2+ content as constant in LCSMO films. At x = 0.71, the peak TCR value was found to be 8.84%/K and corresponding T k was 283.15 K. These results are beneficial for advanced application of uncooling infrared bolometer. [ABSTRACT FROM AUTHOR]

We proposed a method to control and minimize residual stress in [001] preferentially oriented Ti thin films deposited by a Kaufman ion-beam source using a substrate temperature during deposition ( T ) as the parameter. We determined the residual stress, corresponding lattice parameters, and thickness of deposited films using X-ray diffraction and X-ray reflectivity measurements. We showed that the Ti film deposited at T ≈ 273 °C was stress-free with corresponding lattice parameters a 0 and c 0 of (2.954 ± 0.003) Å and (4.695 ± 0.001) Å, respectively. The stress-free sample has the superior crystallographic quality and pure [001] orientation. The Ti thin films were oriented with the c-axis parallel to the surface normal. We also investigated root mean square of surface roughness of deposited films by atomic force microscopy and it was in the range from ≈ 0.58 nm to ≈ 0.71 nm. Such smooth and stress-free layers are suitable for microelectromechanical systems. [ABSTRACT FROM AUTHOR]

Aluminum-doped zinc oxide (AZO) films were deposited on glass substrates with pulsed direct current (DC) magnetron sputtering. Deposition was carried out in both static and dynamic modes. The pulsed DC sputtering process provided a stable deposition of AZO films without arcing, resulting in good crystallinity, unlike simple DC magnetron sputtering. The growth characteristics of the films sputtered on various moving speeds of the in-line dynamic mode are investigated and compared to those of the static mode. AZO films deposited at a moving speed of 120 cm/min showed a dominant (002) orientation, a smooth surface roughness, and a higher figure of merit (FOM), of which properties are similar to those of the static mode. Comparisons of the characteristics obtained at several moving speeds showed that better crystallinity was obtained at the higher moving speed of 120 cm/min. This improvement could be attributed to an averaging effect, which is due to more frequent interruption and initiation of the growth at the higher moving speed. Optical transmission characteristics were compared between the static and dynamic modes, and analyzed in terms of the complex indices of refraction and interference effects of light. [ABSTRACT FROM AUTHOR]

This study examines the effects of sputter deposition growth conditions on IrO 2 thin films developed as electrode layers for Pb(Zr x Ti 1- x )O 3 piezoelectric Micro-Electro-Mechanical Systems applications. For IrO 2 thin-film bottom electrodes sputter deposited on {100}-textured, rutile structure, TiO 2 template layers, the effects of substrate temperature, Ar and O 2 flow rates, and post-deposition anneal were studied. Additionally, the impact of various IrO 2 /Pt bilayer structures on electrode properties were investigated. IrO 2 bottom electrodes grown on 100-oriented TiO 2 at 500 °C with an Ar flow rate of 100 sccm, O 2 flow rate of 60 sccm, and a nominal 100 nm thickness exhibited a film sheet resistance of 9.2 ± 0.2 Ω/sq., surface roughness of 2.3 ± 0.1 nm measured over a 2 μm × 2 μm area, and a rutile structure, preferred-{100} crystalline fiber texture normal to the substrate plane. Furnace-anneal treatments on this electrode at 650 °C for 30 min in 3 SLM O 2 improved its sheet resistance to 7.5 ± 0.2 Ω/sq., and surface roughness was 4.0 ± 0.1 nm. Bilayers of IrO 2 /Pt grown on TiO 2 , with IrO 2 and Pt thicknesses in the 0–100 nm range, were sputter deposited at 500 °C. The electrodes had composite sheet resistances in the range of 1.34 ± 0.03 Ω/sq. to 9.92 ± 0.25 Ω/sq., and surface roughnesses ranging from 1.5 ± 0.1 nm to 2.0 ± 0.1 nm for 2 μm × 2 μm measurement areas. Scanning Transmission Electron Microscopy verified preferred IrO 2 and Pt crystalline fiber textures of {100} and {111}, respectively. [ABSTRACT FROM AUTHOR]

In the ultra large-scale integration process, as chemical mechanical polishing (CMP) is developing to higher precision, nano level planarity and sub-nano level roughness of wafer surfaces become key problems to be overcome. In this work, a theoretical model for local and total material removal was proposed based on the particle sliding trajectories and chemical-mechanical synergy, and the material removal distribution on wafer surface were analyzed. Furthermore, the chemical-mechanical mechanism was studied and synergy maps constructed. It is found that the passivation-wear and additive-synergistic effects dominate the material removal during CMP. This study establishes a correlation mechanism between the nano material removal and global uniformity of wafer surfaces, which provides theoretical and experimental framework for optimizing the slurry and the process parameters. [ABSTRACT FROM AUTHOR]

We demonstrate that femtosecond (fs) laser patterning of Cu can be exploited to realize seed-free deposition of large-area adhesive diamond films on Cu. Fs-laser-induced nanostructures promote diamond nucleation density and result in diamond film formation within a laser fluence window from 2.6 to 3.6 J cm − 2 . Diamond films deposited on Cu surfaces prepared outside this window experience either complete film detachment or formation of low-quality ball-like diamond grains. Diamond/substrate interface roughness plays a critical role in controlling diamond quality and adhesion between substrates and diamond films. Large-area adhesive diamond films have been achieved on Cu substrate surfaces that were first modified with fs-laser irradiation and then scribed into grid patterns. The scribed channels function as expansion joints for stress relief. Strain-free diamond films have been achieved by optimizing the grid size. Using fs-laser processing for seed-free deposition of large-area diamond films on Cu is of great significance for diverse applications, such as thermal management and power electronic devices. [ABSTRACT FROM AUTHOR]

A facile fabrication strategy of multi-functional hybrid thin films of reduced graphene oxide (RGO) and TiO 2 was developed by using layer-by-layer (LBL) assembly of titanium(IV) bis(ammonium lactato)dihydroxide (TALH) and polyallylamine grafted reduced graphene oxide (PAA-RGO) as negatively and positively charged components. The fabrication process of hybrid films was thoroughly characterized by using UV–vis spectroscopic, ellipsometric and atomic force microscopic analysis. This fabrication strategy provided precisely-controlled thickness, surface roughness through 1–10 LBL assembly cycles. By thermal treatment, the PAA-RGO and TALH in the hybrid films were respectively converted into RGO and TiO 2 with the restoration of their electrical conductivity, UV-resistance and photo-catalytic self-cleaning properties. [ABSTRACT FROM AUTHOR]

The development of a simple synthetic technique, based on thermal evaporation for tuning the band gap of molybdenum oxide (MoO 3 ) thin films by doping with cadmium telluride (CdTe) is presented. The pure MoO 3 and CdTe films had amorphous and polycrystalline structures, respectively, and the addition of CdTe to MoO 3 did not show any influence on the structure of the doped films. The surface roughness of the films increased slightly with CdTe concentration. Depth profile analysis demonstrated a uniform distribution of the constituent elements along the depth of the films. Optical measurements confirmed that the films had significant enhancement in the absorption coefficient in the visible region as the concentration of CdTe increased. The optical band gap was reduced from 2.9 eV for pure MoO 3 films to 2.6 eV for the films doped with 10% CdTe. Photolectrochemical characterization showed a steep increase in the photogenerated current densities of the CdTe-doped MoO 3 films due to the reduction of the band gap with CdTe concentration. Such doped films have potential applications in improving the photo-to-current conversion efficiency in solar cells. [ABSTRACT FROM AUTHOR]

The evaluation of bonding mechanisms between magnetron sputtered copper (Cu) thin films and a ceramic substrate was carried out using polycrystalline and monocrystalline alumina (Al 2 O 3 ) substrates with different surface roughness. Three different bonding mechanisms, viz., surface adsorption, mechanical interlocking, and diffusion bonding have been assessed. A tensile test was applied to measure the interfacial adhesion strength between the Cu films and the Al 2 O 3 substrate. The contribution to the interfacial adhesion from each of the bonding mechanisms was elucidated based on the adhesion strength. Without special surface pre-treatment, physical adsorption is the main factor for the film adhesion, contributing ~ 5.9 MPa adhesion strength between this directly sputtered Cu film and a flat Al 2 O 3 substrate. For substrates with surface roughness around 350–500 nm, mechanical interlocking enhances the film adhesion up to 18.6% compared to the flat surface. Post-deposition annealing at 300 °C has increased adhesion strength by 18%, and diffusion bonding may be operative. [ABSTRACT FROM AUTHOR]

Nanocomposite thin films with TiN dispersed in Ni matrix were deposited in an environment having Ar:N 2 = 1:2 on silicon (100) substrate with bias of − 60 V at 300 °C, 500 °C or 700 °C by co-sputtering of Ti and Ni targets used as RF and DC sources, respectively. The structure and properties of these films were compared with those deposited at ambient temperature and then annealed for 1 h in vacuum at above-mentioned temperatures. Whereas < 111 > is the preferred orientation of Ni, transition from < 100 > to < 111 > is observed for TiN at temperatures ≥ 500 °C, as confirmed by XRD analyses. The average grain sizes of Ni and TiN have been found to be in the ranges of 11–25 nm and 6–13 nm, respectively, using both XRD and TEM studies. Transition from compressive to tensile residual stress is observed with increase in substrate temperature for deposition or annealing. Hardness, elastic moduli and scratch-resistance of the films evaluated using a nanoindentor are found to possess the most optimum values on their growth at substrate temperature of 300 °C. [ABSTRACT FROM AUTHOR]

A method for Al thin film surface nanostructuring using Al imprinting with a silicon insert and subsequent anodic oxidation and selective oxide removal for nanostructure thinning and surface smoothing is presented. Al imprinting results in direct pattern transfer of the Si insert pattern, while anodic oxidation results in an increase of the nanostructure pattern aspect ratio due to the observed anodic oxidation anisotropy between the vertical direction and sidewalls. Al lines of 120 nm width and height-to-width ratio of 6 were thus achieved, starting from a Si insert of 500 nm wide lines with a height-to-width ratio of 1, resulting in an effective surface area increase × 2.4, confirmed by a corresponding capacitance density increase of a MIM capacitor using the nanostructured Al thin film as the bottom electrode. The developed method is simple, fast, versatile, and does not require any expensive equipment for its realization. It can be used for the formation of a variety of different nanostructures on the Al surface, for use in a large variety of applications. [ABSTRACT FROM AUTHOR]

• Columnar crystal of coatings coarsened with increase of substrate surface roughness. • Thickness of coatings increased with the increase of substrate surface roughness. • Pickling pretreatment significantly improved adhesion strength of AlTiN coating. • Friction factor of coatings increased with increase of substrate surface roughness. • AlTiN coating on the sandblasted substrate had the best wear resistance. Four different pretreatments (mirror polishing, grinding, sandblasting and acid washing) were performed on TiCN-based cermets substrates. Subsequently, AlTiN coatings were deposited on the four differently pretreated substrates by means of arc ion plating. The microstructure of AlTiN coatings were studied by scanning electron microscope and X-ray diffractometer. The results showed that the AlTiN coatings on differently pretreated substrates exhibited columnar structure with (200) preferred orientation. The columnar crystal of coatings coarsened with the increase of substrate surface roughness under the four pretreatments, and the thickness of the coatings increased. Scratch test showed that the adhesion strength of the AlTiN coating on the pickled substrate increased by 46.8% in comparison with that on the polished substrate. Wear test showed that the average friction coefficient of AlTiN coatings increased gradually with the increase of substrate surface roughness under the four substrate pretreatments. The AlTiN coating on the pickled substrate had the largest grain size and many voids. Therefore, the hardness was low and the wear resistance was poor. The AlTiN coating on the sandblasted substrate had the smallest grain size, and accordingly had high hardness and the best wear resistance. [ABSTRACT FROM AUTHOR]

Magnetoimpedance (MI) effect in electrodeposited NiFeCr thin films on the Cu wire is studied for various doping concentrations of chromium (Cr) ion in the NiFe plating bath. The incorporation of Cr ion results in continuous reduction of crystallite size and surface roughness of the film deposited. The rms surface roughness and crystallite size of the film reduce from 33 nm to 25 nm and 9. 1 nm to 6. 1 nm respectively when the Cr ion concentration in plating bath is increased from zero to an optimal value of 0.06 mM. As a result, the coercivity of the film is reduced from 0.11 kA/m to 0.02 kA/m, resulting in increased magnetic softness as explained by random anisotropy model. The enhanced soft magnetic property reflects in MI ratio improved up to 313% with field sensitivity of 232 % / (kA/m) as compared to MI ratio 168% and sensitivity 104 % / (kA/m) when no Cr ion is introduced. Furthermore, an analytical model of circumferential permeability is used which considers distribution of relaxation time corresponding to domain wall motion and dispersion in circumferential magnetic anisotropy in spin rotation. Fit of the experimental data of impedance with theoretical equation of impedance in conjunction with this analytical model of circumferential permeability yields the material parameters related to circumferential permeability of NiFeCr films. These fitting parameters reveals that inclusion of Cr in permalloy film enhances its maximum value of circumferential permeability about 54% by increasing the contribution of domain wall motion and reducing the dispersion of circumferential anisotropy field. • Effect of Cr doping on the MI of electrodeposited NiFe/Cu wire is studied. • Changes in crystallite size and surface roughness are correlated to MI. • Improved soft magnetic properties due to Cr-inhibited controlled nucleation. • Analytical model of permeability is used to explain the observed features. • Using least square fits to MI data, circumferential permeability is reconstructed. [ABSTRACT FROM AUTHOR]

Within the physical vapor deposition (PVD) high power pulse magnetron sputtering (HPPMS) or high power impulse magnetron sputtering (HiPIMS) is a frequently studied technology in the last years. HPPMS offers the possibility to produce coatings with lower roughness, denser microstructure and better mechanical properties in comparison to direct current magnetron sputtering (dcMS). However, HPPMS is known to have much lower deposition rate due to the low duty cycle compared to dcMS. Therefore, from an economic point of view, dcMS is more effective compared to the HPPMS technology. An approach to overcome this issue is the dcMS/HPPMS hybrid technology, whereby dcMS and HPPMS cathodes are used simultaneously to combine the benefits of both technologies. In hybrid processes, the influence of dcMS and HPPMS on the plasma and coating properties is of crucial interest. Therefore, in the present work measurements on plasma properties as well as on coating properties using dcMS, dcMS/HPPMS hybrid and HPPMS (Cr,Al)N processes were carried out. The (Cr,Al)N coating system as well as the utilized steel substrates were chosen to address the application in plastics processing. In the first step of this work the plasmas of dcMS, dcMS/HPPMS hybrid and HPPMS processes were analyzed. Dependancies of the plasma properties on the type of the process as well as the pulse parameters such as the pulse length t on and the frequency f were investigated. The most significant influence was identified depending on the process type. In the second step (Cr,Al)N coatings were produced using the same process parameters. A similar behavior as with the plasma properties was observed for the coating properties. In the third step the measurements of the plasma and coating properties were correlated. It was proven that changes in the plasma and coating properties correlate significantly. Therefore, the coating development can be simplified through prediction of the coating properties with the more efficient plasma diagnostics. [ABSTRACT FROM AUTHOR]

• Control of Pt orientation using [Ca 2 Nb 3 O 10 ]− nanosheets and deposition conditions. • Deposition of textured (111) Pt films on Si under standard conditions. • Deposition of textured (200) Pt films on Si using adaptive conditions. Platinum (Pt) is a noble metal with low resistivity and resilience to oxidation, which is largely used in microelectronic devices. In order to facilitate the integration of Pt thin films on silicon substrate, we are showing the ability to control their orientation by using [Ca 2 Nb 3 O 10 ]− nanosheets (CNOns) as seed layer. Pt thin films were sputtered on silicon coated by CNOns (CNOns/SiO 2 /Si), and on TiO 2 /SiO 2 /Si substrates for comparison, at temperatures ranging from room temperature up to 625°C. Under pure argon, highly (111) textured Pt thin films were obtained on both substrates, regardless of the deposition temperature. However, by using an oxygen/argon mixture, highly (200) textured films could be obtained, only on CNOns/SiO 2 /Si substrate, when the substrate temperature is above 550°C. X-ray diffraction, scanning electron microscopy, and atomic force microscopy were used to characterize the crystalline quality, thickness, surface morphology and roughness of the Pt thin films. Their resistivity was measured at room temperature by the four-point probes method. [ABSTRACT FROM AUTHOR]

Multilayer nanocrystalline mesoporous titania films were synthesized using the layer-by-layer deposition and surfactant-assisted sol-gel methods on glass substrates. The thickness, morphology and surface roughness of the films were systematically investigated using field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). Multilayer films were manufactured by repeated spin coating followed by heat treatment at 250 °C for 1 h after each deposition, and a final calcination at 400 °C for 4 h. Multilayer films with completely uniform thicknesses between 470 nm–1.85 μm and without clear interfaces were obtained by 1–6 coating cycles. The X-ray diffraction (XRD) analysis demonstrated 9.60 nm anatase crystallites. Interestingly, AFM analysis indicated that the root mean square (rms) surface roughness of the films was significantly reduced from 3.11 to 1.03 nm by increasing the deposited layers from 1 to 6. Moreover, power spectral density ( PSD ) analysis revealed that the roughness exponent and fractal dimension values of all films fall within the range of 0.48–0.53 and 2.47–2.52, respectively. This suggests that while the first titania layer exhibits a coarse microstructure, it acts as an intermediate layer in the formation of improved microstructures by eliminating the lattice mismatch between the glass substrate and subsequent titania depositions. Altogether, our results demonstrate the formation of self-affine surfaces with quite similar dynamics evolution of roughness formation either on the glass substrate or titania layer. [ABSTRACT FROM AUTHOR]

We used numerical simulations based on the finite-element method (FEM) to calculate both the amplitude and phase information of the scattered electric field from random rough surfaces, which can be directly compared to ellipsometric measurements and effective medium approximation (EMA) calculations. FEM can serve as an exploration tool for the relationship between the thickness of the surface roughness evaluated by Bruggeman EMA and the morphological parameters of the surface, such as the root mean square height, the lateral auto-correlation length, and the typical average slope. These investigations are of high interest in case of poly-crystalline and amorphous materials. The paper focuses on the simulations of rough Si surfaces. The ellipsometric calculations from FEM and EMA simulations match for wavelengths of illumination much shorter than the typical feature size of the surface. Furthermore, for these cases, the correlation between the EMA thickness and the root mean square height of the roughness for a given auto-correlation length is quadratic, rather than linear, which is in good agreement with experimental measurements and analytical calculations presented in recent reports. [ABSTRACT FROM AUTHOR]