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In the present paper, the effects of metal ion implantation on the structural and optical properties of TiN thin films have been investigated. TiN films of 170 nm thickness were grown by d.c. reactive sputtering on Si (100) wafers and then irradiated at 5 × 1016 ions/cm2 with either Au, Ag, or Cu ions by using two different energies per each implanted metal. The results showed that as deposited TiN crystallizes in the form of a fcc cubic structure, with the crystallites preferentially oriented along the (111) plane. For all implanted layers, the cubic structure was preserved, but compared to as deposited TiN the crystallites were smaller and the lattice was contracted. These changes were correlated with the depth distribution of Au, Ag and Cu ions and assigned to implantation-induced damage that was larger when higher ion energies were used. High-resolution XPS spectra of the surface of as deposited sample showed the coexistence of TiN, TiO2 and TiOxNy phases and this was related to the surface oxidation of the films due to the exposure to air. After implantation, the results were almost similar for all metals, showing an increase in TiO2 contribution and the formation of pure metallic Au and Ag phases, while copper is in the Cu2+ state, which is attributed to Cu(II)-oxide and Cu(OH)2. The microstructural characteristics including defect formation, changes in crystallite size and lattice contraction, and also growth of different metallic phases during implantations were correlated with the findings of the optical characterization of the implanted films. For the as deposited film we found an energy gap of 2.91 eV, which was lower than the value typical for TiN. After implantation the gap was shifted to higher energies, while at the visible part of the region, the existence of additional energy levels, at photon energies below 2.9 eV was observed. Besides, all implanted films showed degraded photocatalytic activity compared to as deposited TiN, among which Cu-implante

The ion implantation technique has a number of advantages over conventional methods for the improvement of thin films that offer the various possibilities of their use in different industrial and technological fields. Herein, we present the effects of metal ion implantation on the structural and optical properties of TiN thin films. TiN films of 170 nm thickness were grown by d.c. reactive sputtering on Si (100) wafers and then irradiated at 5×1016 ions/cm2 with either Au, Ag, or Cu ions by using two different energies per each implanted metal. The results showed that as deposited TiN crystallizes in form of fcc cubic structure, with the crystallites preferentially oriented along the (111) plane. For all implanted layers the cubic crystallographic structure was preserved, but compared to as deposited TiN the crystallites were smaller and the lattice was contracted. Besides, the surface compositional analysis of as deposited sample showed the coexistence of TiN, TiO2 and TiOxNy phases and this was related to the surface oxidation of the films due to the exposure to air. After implantation, the results were almost similar for all metals, showing an increase in TiO2 contribution and the formation of pure metallic Au and Ag phases, while copper is in the Cu2+ state, which is attributed to Cu(II)-oxide and Cu(OH)2. The microstructural characteristics including defect formation, changes in the crystallite size and lattice contraction, and also growth of different metallic phases during implantations were correlated with the findings of the optical characterization of the implanted films. For as deposited film we found energy gap of 2.91 eV, which was lower than the value typical for TiN. After implantation the gap was shifted to higher energies, while at the visible part of the region, additional energy levels, at photon energies below 2.9 eV were observed. Further, all implanted films showed degraded photocatalytic activity compared to as deposited TiN, among which Cu-im

A set of samples of SrGd2O4 doped with Sm3+ and Dy3+with different concentrations was prepared via glycine-assisted combustion synthesis. All of the diffraction peaks are related to the pure orthorhombic lattice SrGd2O4, according to X-ray Powder Diffraction investigation. The Energy Dispersive X-ray Spectroscopy chemical characterization revealed that the structure included all desired elements. Field Emission Scanning Electron Microscopy was used to capture the morphology, which showed porous aggregated particles consisting of roughly 50 nm-sized spherical particles. The Mercury Intrusion Porosimetry was used to establish where voids originated, and the results showed that samples have a real permanent 3D pore structure. X-ray Photoelectron Spectroscopy verified the successful incorporation of Dy3+ and Sm3+ ions in the matrix. Down-conversion luminescence spectra were recorded and typical emission transitions were found for either Sm3+ (4G5/2→6H5/2, 4G5/2→6H7/2, 4G5/2→6H9/2) or Dy3+ (4F9/2→6H15/2 and 4F9/2→6H13/2) ions. Calculation of the energy band gap using UV-VIS Diffuse Reflectance Spectroscopy yielded values of 4.3 eV for both doped samples. Using UV-VIS Absorption Spectroscopy, the photocatalytic degradation process was observed. After 4 h of simulating Sun exposure, an analysis of the photocatalytic properties revealed that approximately 50% of the Rhodamine B had been mineralized.

Enhanced optical properties of TiO2 thin films can be achieved by doping or coating with metals. Metal-doped TiO2 can reduce electron-hole recombination and increase hydroxyl radical concentration on the surface of TiO2, resulting in increase of the photocatalytic activity. TiO2 and TiO2-Au thin films were obtained by DC magnetron sputtering of Ti target with Ar ions in O2 atmosphere. In the case of Au buffered TiO2 thin films, two different systems were deposited for comparison. Post deposition annealing at 400 °C was carried out in nitrogen atmosphere for 3 h. The structural and optical characteristics of the prepared films were investigated in detail by the combination of high-resolution microscopic and spectroscopic techniques. The photo-degradation rate was measured using Rhodamine B which simulated pollutant. Post deposition annealing resulted in diffusion of Au atoms through the layer as it was revealed by transmission electron microscopy and energy dispersive X-ray spectroscopy. The obtained TiO2 thin films were found to be amorphous after deposition and annealing at 400 °C leads to crystallization of anatase phase. Analysis of the binding energy in the corresponding X-ray photoelectron spectra has confirmed stoichiometry of TiO2 and that concentration of Au on the surface can be controlled by sputtering and annealing conditions, thus changing optical properties by influencing the surface plasmonic nature. All Au doped TiO2 thin films exhibited enhanced wettability and photo-degradation rates when compared to pristine titania films. © 2022 Elsevier B.V.

The influence of deposition and annealing parameters on optical, structural and photocatalytic properties of N-doped titanium-dioxide (TiO2) thin films have been studied. Anatase and anatase-rutile crystalline phase mixture TiO2 thin films were obtained depending on the reactive direct current (DC) sputtering and annealing conditions. Deposition in the nitrogen atmosphere produced N-doped TiO2 thin films with energy gap values shifted towards visible region in comparison with thin TiO2 films deposited without nitrogen in the atmosphere. The role of substitutional and interstitial nitrogen atoms incorporated in obtained crystalline structures during the deposition was shown important and was reflected in the efficiency of photocatalysis. It was found that thin TiO2 films with more substitutional incorporated nitrogen exhibits better photocatalytic properties. These results could be of importance towards achieving controlled synthesis of N-doped TiO2 thin films with desired structural and optical properties, especially with improved photo-activity in the visible part of the solar spectrum.

The subject of this PhD thesis is formation and characterization of TiO2 thin layers deposited by three different physical vapor deposition (PVD) methods. The aim was to define conditions for producing thin layers with optical characteristics that are desirable for photocatalytic purposes. Beside monitoring the impact of deposition parameters during synthesis of TiO2 thin layers, to achieve the aim effects of different annealing conditions were investigated, roles of the oxygen and titanium vacancy places in the crystal lattice and effects of nitrogen doping and role of the nitrogen incorporation sites in crystal lattice on optical and photocatalytic properties were studied. Some of the characterization techniques employed in this research were transmission electron microscopy, Rutherford backscattering spectrometry, X-ray diffraction and spectroscopy techniques: X-ray photoemission and UV/Vis. Experimental results in the thesis are divided into three sections which are referred to PVD method used for deposition of thin films: e-beam assisted evaporation, RF magnetron sputtering and reactive ion sputtering..., Предмет истраживања ове докторске дисертације обухвата формирање танких слојева TiO2 уз помоћ три различите физичке методе депоновања и њихову карактеризацију. Циљ је проналажење најпогодније методе и услова синтезе којом би се добили ТiO2 танки слојеви са оптичким особинама које су пожељне за њихову фотокаталитичку примену. У сврху постизања тог циља поред промене различитих параметара приликом синтезе слојева, посматрани су и ефекти одгревања слојева под различитим условима, улога вакантних места кисеоника и титана у кристалној структури као и ефекти допирања азотом и улога места уградње примесних атома у кристалну решетку на оптичке и фотокаталитичке особине материјала. За карактеризацију добијених слојева најчешће коришћене технике у оквиру ове дисертације су: трансмисиона електронска микроскопија, спектрометрија Радерфордовим повратним расејањем, рендгенска кристалографија и спектроскопске методе: фотоемисија изазвана меким Х-зрацима и UV/Vis. Експериментални део рада је подељен у три целине и то према методама којима су формирани TiO2 танки слојеви: напаравање помоћу снопа електрона, радио-фреквентно реактивно распрашивање и реактивно распрашивање јонским снопом.

The possibility of interlayer mixing in a Ti/Ta multilayer system, induced by laser irradiation, was the main purpose of these experiments. Ti/Ta multilayer system, consisting of ten alternating Ti and Ta thin films and covered by slightly thicker Ti layer, was deposited on Si (100) wafers to a total thickness of 205 nm. Laser irradiation was performed in air by picoseconds Nd:YAG laser pulses in defocused regime with fluences of 0.057 and 0.11 J cm−2. Laser beam was scanned over the 5 × 5 mm surface area with different steps along y-axes. Structural and compositional characterisation was done by auger electron spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy. Laser processing at lower fluence caused only oxidation of the top Ti layer, despite of the number of applied laser pulses. Interlayer mixing was not observed. Application of laser pulses at fluence of 0.11 J cm−2caused partial and/or complete ablation of deposited layers. In partially ablated regions considerable mixing between Ti and Ta films was registered.

Solvothermal synthesis of ZrO2-TiO2 binary oxides and pure counterparts at 150 degrees C in water/isopropanol media is presented. Titanium (IV) isopropoxide and zirconium (IV) propoxide were used as precursors. XRD and TEM techniques were used for structural and morphological characterization of obtained samples. XPS spectra of mixed oxide samples were compared in order to correlate composition of samples with surface properties and presence of defects. Relative positions of defect states within band-gaps of semiconductors were estimated from UCPL spectra. UV-Vis DRS spectra revealed that both pure oxides experienced red shift of absorption thresholds compared to reference data. Photocatalytic activities of all samples were probed under simulated Solar light on three model compounds: phenol, 4-chlorophenol (4-CP) and 2, 4, 6-trichlorphenol (TCP). Pure TiO2 showed the highest photocatalytic activity in the case of phenol. However, pure ZrO2 and binary oxides showed higher photoactivity in degradation of 4-CP and TCP. The activity of wide band-gap semiconductors under simulated Solar light in photodegradation of phenol and its derivatives is most probably the consequence of formation of charge transfer complexes between pollutant molecules and semiconductors surface.

Solvothermal synthesis of ZrO2-TiO2 binary oxides and pure counterparts at 150 degrees C in water/isopropanol media is presented. Titanium (IV) isopropoxide and zirconium (IV) propoxide were used as precursors. XRD and TEM techniques were used for structural and morphological characterization of obtained samples. XPS spectra of mixed oxide samples were compared in order to correlate composition of samples with surface properties and presence of defects. Relative positions of defect states within band-gaps of semiconductors were estimated from UCPL spectra. UV-Vis DRS spectra revealed that both pure oxides experienced red shift of absorption thresholds compared to reference data. Photocatalytic activities of all samples were probed under simulated Solar light on three model compounds: phenol, 4-chlorophenol (4-CP) and 2, 4, 6-trichlorphenol (TCP). Pure TiO2 showed the highest photocatalytic activity in the case of phenol. However, pure ZrO2 and binary oxides showed higher photoactivity in degradation of 4-CP and TCP. The activity of wide band-gap semiconductors under simulated Solar light in photodegradation of phenol and its derivatives is most probably the consequence of formation of charge transfer complexes between pollutant molecules and semiconductors surface.

Formation of periodic nanostructures on the Ti/5x(Al/Ti)/Si multilayers induced by picosecond laser pulses is studied in order to better understand the formation of a laser-induced periodic surface structure (LIPSS). At fluence slightly below the ablation threshold, the formation of low spatial frequency-LIPSS (LSFL) oriented perpendicular to the direction of the laser polarization is observed on the irradiated area. Prolonged irradiation while scanning results in the formation of a high spatial frequency-LIPSS (HSFL), on top of the LSFLs, creating a co-existence parallel periodic structure. HSFL was oriented parallel to the incident laser polarization. Intermixing between the Al and Ti layers with the formation of Al-Ti intermetallic compounds was achieved during the irradiation. The intermetallic region was formed mostly within the heat affected zone of the sample. Surface segregation of aluminium with partial ablation of the top layer of titanium was followed by the formation of an ultra-thin Al2O3 film on the surface of the multi-layered structure. Published by AIP Publishing.

Metallic biomaterials should exhibit excellent biocompatibility, high corrosion resistance and low elastic modulus which are close to that of human bones. It was shown that in this sence Ti-Ta alloys have considerably better mechanical properties compared to pure titanium or tantalum [1, 2]. The main purpose of these experiments was investigation of possibility to induce interlayer mixing in an Ti/Ta immiscible multilayer system by laser irradiation.The absence of interlayer mixing was previously shown on this system during the Ar+ ion irradiation up to relatively high fluence of 2x1016 ions cm-2 [3]. The system consisted of ten alternate Ti and Ta thin films (~18 nm each) and covered by slightly thicker Ti layer (~27 nm) on the top with the purpose of creating an appropriate porous structure very important for potential biocompatibility [4]. Structure was deposited on Si (100) wafers to a total thickness of 205 nm. Laser irradiation was performed in air by picoseconds Nd: YAG laser. Defocused laser pulses had a laser spot on the sample surface of 3 mm in diameter and fluences of 0.057 and 0.11 J cm-2 . Laser beam was scanned over the 5x5 mm2 surface area with different steps along y-axes to provide a variation in deposited energy density. For structural and compositional characterisation following methods were used: Auger electron spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and scanning electron microscopy. The obtained results show that laser processing at a lower fluence causes only oxidation of the top Ti layer, invariable to the number of applied laser pulses and no interlayer mixing was observed. Appliance of laser pulses at fluence of 0.11 J cm-2 , on the other hand, caused significant increase of surface roughness and partial and/or complete ablation of deposited layers, but in partially ablated regions considerable mixing between Ti and Ta films was registered. These experiments indicate that the use of picoseconds laser pulses w

The influence of deposition and post-deposition annealing parameters on the structure and optical properties of TiO2 thin films synthesized by reactive e-beam evaporation is reported. Pure Ti (99.9%) was evaporated in oxygen atmosphere to form thin films on Si (100) and glass substrates. Depositions were conducted on substrates held at room temperature and at 200-400 degrees C heated substrates. Post-deposition annealing was done for 3 h at 500 degrees C in air. Compositional and structural studies were performed by Rutherford backscattering spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy, and optical properties were studied by ultraviolet-visible spectroscopy and analytically by pointwise unconstrained minimization approach method. It was found that both the structure and optical properties of the films are strongly influenced by the deposition and processing parameters. All deposited samples showed good stoichiometry of Ti:O similar to 1:2. Depending on the substrate temperature and oxygen pressure in the chamber during the deposition, anatase-rutile mixed films were obtained, and in some cases TiO and Ti2O3 phases were observed. Substrate deposition temperature appears to play the major role on the final structure of the films, while post-deposition annealing adds up for the lack of oxygen in some cases and invokes crystal grain growth of already initiated phases. The results can be interesting towards the development of TiO2 thin films with defined structure and optical properties. (C) 2015 Elsevier B.V. All rights reserved.

The effects of helium ion irradiation on immiscible AlN/TiN multilayered system were studied. The structure consisted of 30 alternate AlN (similar to 8 nm) and TiN (similar to 9.3 nm) layers of a total thickness around 260 nm, deposited on (100) Si substrates by reactive sputtering. The system was then implanted with 30 keV He+ to very high irradiation doses, 1-4 x 10(17) ions/cm(2). Evaluated projected ion range was 153.1 +/- 45.4 nm and maximum displacements per atom for the applied doses from 6 to 24. It was found that the multilayers remained well separated and stable after irradiation to 1 x 10(17) ions/cm(2), which introduces up to 10 at.% of He within the structure. The main effects were agglomeration of He bubbles around the projected ion range, mostly concentrated at the AlN edges of the interfaces, and a slight increase of the mean grain size within the affected zone. Increasing of the ion dose induced further agglomeration of bubbles, splitting of the layers at the interfaces, and final destruction of the structure. The evaluated He content was consistent with the implanted dose up to 2 x 10(17) ions/cm(2). For the highest dose the implanted gas is partially released from the structure. The results can be interesting towards the development of radiation tolerant materials. (C) 2015 Elsevier B.V. All rights reserved.

The influence of sputtering parameters and annealing on the structure and optical properties of TiO2 thin films deposited by RF magnetron sputtering is reported. A pure TiO2 target was used to deposit the films on Si(100) and glass substrates, and Ar/O-2 gas mixture was used for sputtering. It was found that both the structure and the optical properties of the films depend on deposition parameters and annealing. In all cases the as deposited films were oxygen deficient, which could be compensated by post deposition annealing. Changes in the Ar/O-2 mass flow rate affected the films from an amorphous like structure for samples deposited without oxygen to a structure where nano crystalline Futile phase is detected in those deposited with O-2. Annealing of the samples yielded growth of both, ruffle and anatase phases, the ratio depending on the added oxygen content. Increasing mass flow rate of O-2 and annealing are responsible for lowering of the energy band gap values and the increase in refractive index of the films. The results can be interesting towards the development of TiO2 thin films with defined structure and properties. (C) 2015 Elsevier EN. All rights reserved.

The effects of high dose Ar ion irradiation on immiscible AlN/TiN multilayered structures were studied. The structures with 30 alternate layers of a total thickness of similar to 260 nm were deposited by reactive sputtering on (100) Si wafers. Individual layer thickness was similar to 8 nm AlN and similar to 9.3 nm TiN. Irradiation was done with 180 keV Ar+ ions to 1x10(16)-8x10(16) ions/cm(2), with the projected range around mid-depth of the structures. It was found that the highest applied dose induced a considerable intermixing, where the growing TiN grains consume the adjacent AlN layers, transforming partly to (TiAl)N phase. Intermixing occurs due to a high contribution of collision cascades, which was not compensated in demixing by chemical driving forces. However, a multilayered structure with relatively flat surface and interfaces is still preserved, with measured nano-hardness value above the level for the as-deposited sample. The results are compared to other systems and discussed in the light of the existing ion beam mixing models. They can be interesting towards better understanding of the processes involved and to development of radiation tolerant coatings. (C) 2013 Elsevier B.V. All rights reserved.

The effects of argon ion irradiation on structural changes in Ta/Ti multilayers deposited on Si wafers were investigated. The starting structures consisted of sputter deposited 10 alternate Ta (similar to 23 nm) and Ti (similar to 17 nm) layers of a total thickness similar to 200 nm. They were irradiated at room temperature with 200 key Ar(+), to the fluences from 5 x 10(15) to 2 x 10(16) ions/cm(2). The projected ion range was around mid-depth of the multilayered structure, and maximum displacements per atom similar to 130. It was found that, despite of the relatively heavy ion irradiation, individual nanocrystalline Ta and Ti layers remain unmixed, keeping the same level of interface planarity. The changes observed in the mostly affected region are increase in lateral dimensions of crystal grains in individual layers, and incorporation of bubbles and defects that cause some stretching of the crystal lattice. Absence of interlayer mixing is assigned to Ta-Ti immiscibility (reaction enthalpy Delta H(f) = +2 kJ/mol). It is estimated that up to similar to 5 at.% interface mixing induced directly by collision cascades could be compensated by dynamic demixing due to chemical driving forces in the temperature relaxation regime. The results can be interesting towards developing radiation tolerant materials based on multilayered structures. (C) 2011 Elsevier B.V. All rights reserved.