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• Black titania (H-TiO 2-x) films obtained by hydrogen plasma treatment in MPCVD. • Surface of black titania film but not pristine TiO 2 are deactivated after MB degradation. • Surface of black titania film analysed with XPS and SIMS. • Surface of black titania film regenerated with a light treatment. • SIMS depth profiling revealed hydrogen and defects gradients in the black film. Thin film black titania (H-TiO 2-x) was obtained in hydrogen plasma in an MPCVD system. The photocurrent and the methylene blue (MB) photodegradation rate of the black titania increased drastically compared to the pure anatase sample. A major difference between pristine and black titania films in photocatalytic deactivation by MB was found. Pristine TiO 2 thin films were not deactivated after a series of MB degradation measurements followed by rinsing with DI-water, while the photocatalytic activity of H-TiO 2-x dropped by 50%. It was shown that the deactivated sample can be regenerated with a process that consists of exposure of the deactivated sample to UV-VIS light in DI-water. It was found that due to the presence of hydroxyl groups on the surface, as well as an upward band bending on the surface of the black photocatalyst, the products of MB degradation during the photocatalytic reaction are being chemically bonded to the surface of H-TiO 2-x , but not pristine TiO 2. Based on the new results, a new description of thin film black titania is provided. [ABSTRACT FROM AUTHOR]

This study investigated the annealing effects on structural and mechanical properties of pure (pure TiO 2 ) and carbon doped titania (C-TiO 2 ) thin films. The amorphous films of pure TiO 2 and C-TiO 2 were deposited on the substrates of Si wafer (100) at 100 °C by reactive magnetron sputtering. Through annealing at different temperatures, times and atmospheres, the crystallinity and defect density of the films could be varied. Under H 2 annealing, oxygen vacancies are generated in the films which facilitate the phase transformation from amorphous to anatase at a lower onset temperature than those under air annealing. The onset temperature of crystallization for C-TiO 2 is higher than that for pureTiO 2 due to the existence of carbon atoms which impairs the diffusion of Ti and O atoms for crystallization. The hardness of the films by nano-indentation test ranges from ~ 7 GPa for the amorphous to ~ 12 GPa for the crystallized films and is affected by the phase, degree of crystallinity, grain size and defect density. When the amorphous titania film fully transforms to a crystalline phase of small grains at temperatures ranging from 300 to 500 °C, its hardness will reach a maximum. However, at temperatures over 400 to 500 °C, the film hardness declines conversely with increasing temperatures or extending annealing time due to increase in grain size and change in defect density. [ABSTRACT FROM AUTHOR]

Abstract: Boron nitride films and nanostructures are deposited by the reaction of B2H6 and NH3 in H2 via biased microwave plasma-assisted chemical vapor deposition. One-dimensional boron nitride nanostructures (BNNSs) are observed on the BN layers by the processing of diamond/BN multilayer under ion-bombardment and plasma etching. At a substrate bias of −100 V, the morphologies of the BNNSs evolve from dense film to nanocorns to nanotips, when the number of the diamond/BN bi-layer increases. Various phases of boron nitride including amorphous-BN, hexagonal h-BN, turbostratic t-BN, rhombohedral r-BN, explosion E-BN, wurtzitic w-BN and cubic c-BN are detected in the BNNSs. The BN nanotips observed are considered to result from the tip structure growth from the combined effects of ion bombardment and plasma etching. [Copyright &y& Elsevier]

Room temperature ferromagnetism (FM) is observed for annealed heavily niobium doped titania (TNO) thin films on silicon substrates and on glass nanospheres. Precipitation of ~10–30nm-diameter Nb2O5 nanoparticles occurs in the TNO films air-annealed at 600°C or above and enhances their saturation magnetization (Ms). The largest Ms is found in the 800°C annealed 40nm-thick TNO films on glass nanospheres (~6×104 A/m) and the Ms reduces as films increased in thickness or deposited on flat Si substrates or annealed at lower temperature or in hydrogen. This work demonstrates that nano-precipitates and interfaces are both significant factors in achieving enhanced FM in the titania based thin films. [ABSTRACT FROM AUTHOR]

Abstract: The effects of crystallinity, phase and oxygen vacancies on optical and photocatalytic properties of titania (TiO2) thin films were systematically studied. The as-deposited amorphous titania films were prepared by reactive sputtering titanium metal targets in argon–oxygen plasma at 100°C and subsequently annealed at various temperatures of 400–800°C in air, vacuum and H2 atmosphere. The results indicate that in general the crystallinity of the annealed films is enhanced with the increasing annealing temperature. At the same temperature, the H2 annealed films achieve better crystallinity but containing more oxygen vacancies than the films annealed in air and in vacuum. In H2 or in vacuum, the concentration of oxygen vacancies in the annealed films increases with increasing temperature, while in air it remains constant. Oxygen vacancies in titania film not only facilitate phase transformation but also lower the band gap of titania, and make the film visible-light responsive. Photocatalytic properties of the TiO2 films were characterized in UV and visible light irradiation by following the Ag reduction and degradation of methylene blue. The films annealed at 600–700°C in H2 possess the best film crystallinity and the proper concentration of oxygen vacancies and exhibit the best photocatalytic performance under both UV and visible light. [Copyright &y& Elsevier]

Abstract: Sculptured porous titania films as photoanode in dye-sensitized solar cell (DSSC) were prepared using an electron-beam evaporation system with glancing angle deposition (GLAD) method. By controlling the substrate rotation rate and the incident angle of evaporant, titania films of various thicknesses were prepared on ITO glasses. The as-deposited nano-porous films are comprised of helical nano-columns and assembled in an orderly manner with gaps or pores in between, which offer large internal surface area for dye adsorption and direct electron transfer path. There is a positive correlation between the film thickness, film effective surface area, amount of absorbed dye and cell efficiency. The nano-porous films provide a synergistic effect of high surface area, effective route for electron transfer, tight interfaces, and enhanced light trapping, which are all beneficial for higher cell efficiency. The DSSC consisting of a 6μm titania film, deposited at substrate rotating rate 0.17rpm and incident angle 73°, gave a cell efficiency of 6.1%. [ABSTRACT FROM AUTHOR]

Abstract: Multi-element AlxCoCrCuFeNi (the molar ratio of x =0.5, 1, and 2) oxide thin films were deposited by reactive sputtering of homogeneous alloy targets. The as-deposited films comprise single cubic-(c-) spinel crystalline phase. The films post-annealed at 500 °C for 5 h in air reveal no phase transformation and no obvious grain growth. Those post-annealed at higher temperature, 700 and 900 °C, show possible formation of tetragonal-(t-) and orthorhombic-(o-) spinel phases resulting in a c/t/o mixed phase as well as precipitates of copper-rich oxide nanorods on the film surface. The amount of c-spinel in the mixed phase increases with increasing x value. The density of the precipitates is dependent on both x value and annealing temperature. Hardness increases for films annealed at 500 °C with the highest value of hardness of 25.7±2.3 GPa. Higher annealing temperatures result in formation of cracks and holes on the films that make the nanoindentation measurements unreliable. [Copyright &y& Elsevier]

Abstract: Visible light responsive carbon doped TiO2 films were developed by ion-assisted electron-beam evaporation using rutile powder as source material and two different gases, CO2 and CO in the ion source as dopant source. The influence of beam current on the carbon content and crystallinity of the films was systematically studied to understand their effect on photocatalytic activity. More carbon content was incorporated when ion beam current was raised and when CO2 gas was utilized as the ion source and it also resulted in shifting the absorbance edge of TiO2 towards higher wavelength region. The TiO x C y film of well-crystallized anatase phase with 1.25at.% carbon dopant from CO2 source exhibited the lowest contact-angle close to zero and the best photocatalytic activity in terms of the reduction of silver ions to metallic silver and the degradation of methylene-blue under visible-light illumination. Post annealing the films at a higher temperature (500°C) also improved the overall photocatalytic activities. This work demonstrates clearly that the photocatalytic performance of the TiO x C y films under visible light correlates well with the anatase crystallinity and carbon dopant concentration. [Copyright &y& Elsevier]

Abstract: Carbon-incorporated titanium oxide (TiO x C y ) films in anatase structure were deposited by co-sputtering titanium and graphite targets in argon and oxygen. The incorporation of carbon into TiO2 retained the crystallinity of anatase phase and the carbon is a mix of both graphitic as well as substitutional in nature. The microstructure of the TiO x C y films consisted of columnar carbon-doped titania grains covered with graphitic carbon along the grain boundaries. The films exhibited absorption bands in the visible light region with an absorption edge red-shifted up to ∼450 nm corresponding to a band gap ∼2.7 eV and while absorption tails continued to above 700 nm. The films possessed outstanding visible light-induced photocatalytic properties in the reduction of silver ions, degradation of methylene blue and superhydrophilicity. [Copyright &y& Elsevier]

Abstract: Hex-element Al x CoCrCuFeNi (x =0.5, 1, 2) metallic and oxide films were deposited by sputtering homogeneous alloy targets in argon and argon–oxygen plasma, respectively. The metallic films are primarily composed of simple face-centered and/or body-centered cubic phases, while the oxide films comprise only a cubic-spinel crystalline phase. The aluminum content plays an important role in the structure and properties of both the metallic and the oxide Al x CoCrCuFeNi films. The lattice constant increases for both the face-centered and the body-centered cubic metallic phases while it decreases linearly for the spinel phase with increasing x value. The oxide films are nanocomposite in nature and their film hardness is enhanced by both aluminum and oxygen content with the highest hardness of 22.6±1.6 GPa being achieved in this series of films. [Copyright &y& Elsevier]

Abstract: Nitrogen-doped titanium oxide (TiO x N y ) films were prepared by reactive magnetron sputtering of a titanium metal target in gas mixtures of argon, oxygen and nitrogen. Two types of nitrogen species are formed in the films following the fraction of N2 (FN2 ) in the reactive atmosphere. One is substitutional nitrogen in anatase titania phase and the other is nitrogen in TiN phase. In a large range of FN2 from 0 to 0.57, TiO x N y films in anatase structure with about 1.0–1.4 at.% substitutional nitrogen are produced and the films exhibit red shifts to ∼500 nm from the absorption edge of ∼380 nm of undoped TiO2. The nitrogen is readily doped in the films by energetic nitrogen ions in the plasma and the films exhibited photocatalytic properties under visible light. When excess nitrogen is supplied as the FN2 above 0.75, the resulting film contains 20.8 at.% of nitrogen with formation of TiN that makes the film opaque and destroys the photocatalytic activity largely. [Copyright &y& Elsevier]

Abstract: Multi-element high-entropy alloys (HE alloys) are new alloys with over five principal elements each having an atomic percentage no more than 35%. Using the alloys, e.g. Al0.5CoCrCuFeNi, Al2CoCrCuFeNi, and AlCrNiSiTi, as target materials in reactive sputtering, nanostructured metallic and nitride films were deposited. XRD patterns show that the alloy films of Al x CoCrCuFeNi are crystalline with structures of simple fcc or mixed bcc+fcc solid solution, and the crystallinity decreases and approaches an amorphous structure with increasing nitrogen flow rate into the processing chamber. Unlike the Al x CoCrCuFeNi HE alloys, the metallic film of AlCrNiSiTi is amorphous and its hardness is much higher than the hardest nitride films of Al x CoCrCuFeNi alloy. TEM, FESEM and AFM observations show that the films morphology and structure evolution with N2/Ar fraction is different between Al x CoCrCuFeNi and AlCrNiSiTi HE alloys. The slope of films resistivity versus N2/Ar ratio is much steeper in AlCrNiSiTi than in Al x CoCrCuFeNi HE alloy. The hardness enhancement in nitrides is less significant in AlCrNiSiTi than in Al x CoCrCuFeNi HE alloys. [Copyright &y& Elsevier]

• Reactively cosputtered ~530 nm polycrystalline LBSO films of ~90 % transparency. • At 650 oC film of low resistivity of 3.4 x 10-3 Ω.cm and mobility of 21 cm2/V-s. • Film crystallinity and mobility increase up to 650 oC and deteriorated over 650 oC. • Oxygen vacancies, La doping and carrier concentration increases with temperature. Lanthanum doped barium tin oxide (LBSO) film is an impressive alternative for expensive transparent conducting oxides film such as indium tin oxide. The LBSO films are grown on quartz substrate by co-sputtering a barium tin oxide ceramic target and a lanthanum metal target in Ar/O 2 plasma at different substrate temperatures ranging from 500 oC to 730 oC keeping all the other parameters constant. The resulting LBSO films are all polycrystalline in nature and their thickness varies from 520-540 nm. UV-visible absorption spectra of the films show blue shift and increasing optical band gap with increasing substrate temperatures. As the substrate temperature arises up to 650 oC, the optical transparency, Hall mobility, carrier concentration and electrical conductivity of the films all increase due to improving film crystallinity, more oxygen vacancies and higher La dopant incorporation. At optimum substrate temperatures at and above 650 oC, the representative values of optical transmittance, mobility, carrier concentration, and resistivity are ~90 %, 21 cm2/V-s, 5.5 x 1019 cm-3 and 3.4 x 10-3 Ω.cm, respectively. This understanding of varying substrate temperature effect on crystal structure, morphology, electrical, and optical properties of thin film can be further utilized to explore various transparent conducting oxide applications. [ABSTRACT FROM AUTHOR]

Pure titanium dioxide TiO2 photocatalytic substrates exhibit antibacterial activity only when they are irradiated with ultraviolet light, which comprises high-energy wavelengths that damage all life. Impurity doping of TiO2-related materials enables visible light to stimulate photocatalytic activity, which enhances opportunities for TiO2 to be used as a disinfectant in living environments. Boron-doped TiO2 displays visible-light-responsive bactericidal properties. However, because boron-derived compounds also exert notable antibacterial effects, most reports did not clearly demonstrate the extent to which the bactericidal property of boron-doped TiO2 is contributed by visible-light-stimulated photocatalysis. In addition, TiO2 thin films have considerable potential for applications in equipment that requires sterilization; however, the antibacterial properties of boron-doped TiO2 thin films have been examined by only a few studies. We found that boron-doped TiO2 thin films displayed visible-light-driven antibacterial properties. Moreover, because boron compounds may have intrinsic antibacterial properties, using control groups maintained in the dark, we clearly demonstrated that visible light stimulated the photocatalysis of boron-doped TiO2 thin films but not the residue boron compounds display antibacterial property. The bactericidal effects induced by visible light are equally potent for the elimination of the model organism Escherichia coli and human pathogens, such as Acinetobacter baumannii, Staphylococcus aureus, and Streptococcus pyogenes. The antibacterial applications of boron-doped TiO2 thin films are described, and relevant perspectives discussed. [ABSTRACT FROM AUTHOR]

• Polycrystalline La doped BaSnO 3 transparent conducting oxide films deposited by sputtering. • Relationship in structural, optical and electrical properties was established. • Effect of oxygen vacancies with varying O 2 partial pressure was demonstrated. • High conductivity of 0.67 × 102 Ω−1 cm−1 and transmittance ~80% achieved for 0.05 Pa. • Figure of merit calculated for as-deposited polycrystalline thin films. Single crystal film of La doped BaSnO 3 (LBSO) has been reported with excellent conductivity and transparency but in order to improve its applicability, it is important to grow polycrystalline LBSO films on inexpensive substrate. A series of polycrystalline LBSO thin films of ~570 nm in thickness are grown on quartz substrate by radio frequency magnetron sputtering at different oxygen pressures varying from 0 to 0.13 Pa. Both carrier concentration and mobility of the films seem to be decreasing with increasing oxygen pressure. The estimated values of mobility, carrier concentration and conductivity are 5.21 cm2/V s, 9.1 × 1019 cm−3 and 2.8 × 102 Ω−1 cm−1, respectively, with optical transmittance of 68% for the film deposited at lowest oxygen partial pressure (0.01 Pa). The optical transmittance of the films improves significantly upto 82% with increasing oxygen pressure to 0.13 Pa. The suitable condition for deposited films is observed at 0.05 Pa in terms of transmittance (~80%) and conductivity (0.67 × 102 Ω−1 cm−1) which is almost 8 times superior to previously reported conductivity (9 Ω−1 cm−1) for polycrystalline LBSO films and comparable to the conductivity (102 Ω−1 cm−1) of the hetero-structured LBSO thin films. Overall, understanding of changes in microstructure, electrical and optical properties of thin film by varying oxygen pressure have been reported effectively. The LBSO films prepared in the current work could be further utilized in TCO applications. [ABSTRACT FROM AUTHOR]

A series of TiO x (0 < x ≤ 2) thin films with different O/Ti ratio were deposited on Si substrates by reactive magnetron sputtering of Ti metal in Ar + O 2 plasma. The influence of oxygen flow rate and substrate temperature on the structural, mechanical, and electrical properties of the films was explored. With increasing the oxygen flow rate, the following phases appeared in the following order: Ti metal, Ti(O) solid solution, TiO, Ti 2 O 3 , Magnéli phases, rutile and anatase TiO 2. With increasing the temperature, the crystallinity, and oxygen content of the films varied, which resulted in changes in film properties. The trend of hardness and electrical conductivity in ceramic TiO x films is TiO > Ti 2 O 3 > Magneli phases > rutile phase. • Reactive sputtering is effective to prepare TiO x films of various O/Ti ratios. • Ti and Ti(-O) solid solution, TiO, Ti 2 O 3 , and Magnéli (Ti n O 2n-1) phases formed. • Film crystallinity improved with increasing substrate temperature. • Electric conductivity increases with high substrate temperature and low O/Ti ratio. • Hardness of ceramic TiO x films: TiO > Ti 2 O 3 > Magneli phases. [ABSTRACT FROM AUTHOR]

The article reports combined effects of Ar addition and substrate bias on the grain size, microstructure, and growth rate of the diamond films prepared in microwave plasma-enhanced chemical vapor deposition. The nanocrystalline diamond (NCD) films with grain size of 50-100 nm, characterized by Raman spectra, scanning and transmission electron microscopy, were produced at 90-99 vol% Ar concentration under -50 V substrate biasing. The growth rate of the NCD films was 0.7-0.8 μm h[SUP-l], larger apparently than those grown by only Ar addition or by substrate bias effect alone. The NCD formation by various mechanisms is discussed, and a revised C[SUB2] insertion mechanism by the promotion of H[SUP+] ions is proposed to interpret the higher growth rate of the NCD films. [ABSTRACT FROM AUTHOR]

The influence of negative substrate bias on the crystallinity, morphology, and growth rate of the diamond films deposited using microwave plasma-enhanced chemical vapor deposition in 1% CH[sub 4]/H[sub 2] plasma were investigated. The nanocrystalline diamond films were produced exclusively under the biasing at -250 V. With -50 V biasing, faceted (111) microcrystalline diamond films at higher growth rate than no-bias samples were produced. When the biasing between - 100 and -200 V, faceted (100) diamond films with decreasing grain size were favored, and the growth rates were gradually reduced along with the increasing biasing. The results indicate that the etching efficiency of H[sup +] ions is enhanced with the increasing kinetic energy obtained from the increasing bias voltage. On the other hand, CH[sup +, sub x] ions at -250 V biasing would have sufficient energy to perform the ion subplantation model to grow the nanocrystalline diamond films by bias-enhanced nucleation. [ABSTRACT FROM AUTHOR]

Discusses a study that presented results of detailed nanoindentation studies of CN[subx] films prepared under a wide range of conditions. Description of carbon nitride thin films; Techniques that failed in synthesizing crystalline B-C[sub3]N[sub4]; Strategies to promote the crystalline; Area in which surface mobility of atoms may be enhanced.

Photocatalysts produce free radicals upon receiving light energy; thus, they possess antibacterial properties. Silver (Ag) is an antibacterial material that disrupts bacterial physiology. Our previous study reported that the high antibacterial property of silver nanoparticles on the surfaces of visible light-responsive nitrogen-doped TiO2 photocatalysts [TiO2(N)] could be further enhanced by visible light illumination. However, the major limitation of this Ag-TiO2 composite material is its durability; the antibacterial property decreased markedly after repeated use. To overcome this limitation, we developed TiO2(N)/Ag/TiO2(N) sandwich films in which the silver is embedded between two TiO2(N) layers. Various characteristics, including silver and nitrogen amounts, were examined in the composite materials. Various analyses, including electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and ultraviolet-visible absorption spectrum and methylene blue degradation rate analyses, were performed. The antibacterial properties of the composite materials were investigated. Here we revealed that the antibacterial durability of these thin films is substantially improved in both the dark and visible light, by which bacteria, such as Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus, and Acinetobacter baumannii, could be efficiently eliminated. This study demonstrated a feasible approach to improve the visible-light responsiveness and durability of antibacterial materials that contain silver nanoparticles impregnated in TiO2(N) films. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • With hydrogen in plasma anatase turns into rutile, then amorphous then mixed oxides. • Optical absorbance turns flat in the visible region for the rutile stage. • O H content of the black shell can reach 80% on the surface. • Electrical conductance of the black shell is much less than for noble metals. • Crystalline core is required to achieve high photocatalytic properties. Abstract Black titania films that resemble the shell of recently reported black TiO 2 , were deposited by DC sputtering a conductive TiO 2 target in a hydrogen-containing plasma. Synchrotron radiation was used for identifying the phases present in the samples. Anatase- defective rutile transformation, with further amorphization and transformation into intermediate Ti oxides were observed. Samples became black and conductive at the stage of transformation into defective rutile and the amorphous sample showed flat absorbance in the visible region. The amount of O H groups on the film surface reaches 80% with increasing hydrogen in the plasma. Nevertheless, the black samples are inferior photocatalytically to transparent titania. Based on the results, some new insights into the phenomenon of black TiO 2 are provided. [ABSTRACT FROM AUTHOR]

Boron-doped titanium dioxide (B-TiO 2 ) films were deposited by reactive magnetron co-sputtering from metallic titanium (Ti) and titanium diboride (TiB 2 ) targets in Ar/O 2 plasma. The films were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Ultraviolet–visible (UV–vis) spectroscopy. The photocatalytic activities of the samples were evaluated for degradation of methylene blue (MB) under UV and visible light irradiation. By changing the TiB 2 target power, various boron amount and species are formed in the as-deposited and the annealed films. Therein, the [BO 3 ] as well as [Ti 2 BO 2 ] species would redshift the UV–visible absorption edge and improve the visible light activity of TiO 2 . Most of the B-species could be oxidized into B 2 O 3 phase and evaporated in the annealed films. This introduced porosity into the films and apparently promoted the UV-light photocatalytic activity. The remaining B 2 O 3 phase itself has no direct effect on the photocatalytic activities, but in couple with TiO 2 they can reduce the recombination rate of the photogenerated carriers, and hence improve the photocatalytic activities of the annealed B-TiO 2 films. [ABSTRACT FROM AUTHOR]

Abstract: Pure titania (TiO2) and carbon containing titania(C-TiO2) thin films were prepared by reactive sputtering in argon–oxygen plasma at 100°C. The as-deposited thin films were amorphous and subsequently annealed at various temperatures of 280–800°C in air and H2 atmosphere. The effects of annealing on the films were systematically studied in terms of phase transformation, activation energy, crystallinity, oxygen vacancies and their photocatalytic properties. The as-deposited TiO2 transforms to anatase at a much lower temperature than the C-TiO2. At the same temperature, the H2-annealed films achieve better crystallinity than the air-annealed films. The activation energies of phase transformation from amorphous to anatase are 180 and 168kJ/mol for the air- and the H2-annealed pure TiO2 films, respectively. The result also shows that the C-TiO2 requires higher temperature or more energy for phase transformation than the pure TiO2. [Copyright &y& Elsevier]

Abstract: In this research, we successfully prepared p-type ZnO films by rapid thermal annealing (RTA) of As doped ZnO films deposited by magnetron DC sputtering using target made of ZnO mixed with Zn3As2 powders. From the Hall measurement, the doped ZnO film converted from n-type to p-type after RTA of the films at 1000°C for 30s. But it converted to n-type conduction again for higher annealing temperature. The X-ray diffraction (XRD) data indicates the crystallinity of the doped films is improved by increased RTA temperature. We also found that rapid thermal annealing (RTA) results in As–O bonding shift toward higher binding energy. It is an indication of the formation of AsZn–2VZn defect, which is responsible for p-type behavior. Further higher annealing temperature increases oxygen vacancies that may compensate the p-type behavior. Thus the RTA temperature is so critical to form AsZn–2VZn while not to form oxygen vacancies. This partially explains that the p-type ZnO is difficult to prepare. [Copyright &y& Elsevier]

Abstract: This study presents a description of the enhancement of light absorption in thin-film silicon (Si) solar cells by using sculptured titania (TiO2) films. We used an electron-beam evaporation system with a glancing angle deposition (GLAD) method to deposit porous TiO2 films on fluorine-doped SnO2 (FTO) substrates. The GLAD TiO2/FTO films were used as conductive electrodes in hydrogenated microcrystalline silicon (μc-Si:H) solar cells. Transmission electron microscopy revealed that the GLAD TiO2 films are composed of sculptured nano-pillars on an FTO surface, and this nanostructure provides a synergistic route for light scattering enhancement. The GLAD TiO2/FTO exhibited a 68% improvement of optical haze (at λ=600nm). The μc-Si:H solar cells consisting of the GLAD-nanostructured TiO2 resulted in a 5% improvement of short-circuit current (Jsc) and yielded a cell efficiency of 6.6%. [Copyright &y& Elsevier]

Abstract: Tungsten oxide (WO3) films were deposited by DC magnetron sputtering of tungsten target in O2/Ar atmosphere. The structures of the films following the various O2 flow rate in a fixed Ar gas supply were investigated by X-ray diffraction patterns, Raman spectra and transmission electron microscopy. The electrochromic properties were characterized by a cyclic voltammetry and UV–vis absorption spectra. The results show that nanocrystalline WO3 film with crystallite size about 10–20nm, deposited at 16sccm O2, has larger charge capacity and coloration efficiency than the other amorphous films. Post-annealing the film at 200°C would create 30–50nm nanocrystalline film, whose electrochromic properties are promoted further due to even larger internal volume, essential to conduct ions and electrons for electrochromic intercalation. However, the electrochromic property deteriorates apparently in the film with 60–100nm nanocrystallites annealed at 300°C, which may be caused by another electrochromism occurring always in the well-crystallized WO3 films. [Copyright &y& Elsevier]

Abstract: Nitrogen-doped titanium oxide (TiO2−xNx) films were prepared by ion-assisted electron-beam evaporation, using rutile powder as source material. The films deposited with nitrogen ion bombardment at various nitrogen partial pressures (PPN2), were investigated by X-ray diffraction patterns, Raman, UV–Vis absorption and X-ray photoelectron spectra. Well-crystallized anatase TiO2 was deposited first without the nitrogen ion bombardment. With nitrogen ion bombardment under increasing PPN2, the TiO2−xNx films with the absorption edges red-shifted toward 500 nm were formed. The films are still in anatase phase but possessed substitutional nitrogen atoms and chemisorbed molecular N2. The films exhibited significant photocatalytic and hydrophilic properties under visible light. The films with 1.8 at.% of nitrogen, deposited at PPN2=3.1×10−2 Pa, exhibit the lowest contact-angle of 3° and the best photocatalytic activity on the degradation of methylene-blue with a rate-constant (k) about 0.293 h−1. The series of films exhibit a consistent relationship among structures, red-shift in visible light absorption, and visible light-induced the hydrophilicity and photocatalysis. [Copyright &y& Elsevier]

Titanium oxide films were deposited in an electron-beam evaporation system using rutile TiO2 as a source material. The films deposited with various oxygen (O2) pressures were investigated by X-ray diffraction patterns, Raman, UV–Vis absorption, X-ray photoelectron spectra and atomic force microscopy. The UV-induced hydrophilicity of the films was measured by the water contact angle variation. The best hydrophilicity was obtained on the well-crystallized anatase TiO2 film deposited with 0.5 × 10−4 Torr (0.7 × 10−2 Pa) O2 pressure. However, the film deposited without O2 supply contains some amorphous TiO2−x species, which retard apparently the hydrophilicity. When the O2 supply is increased over 0.5 × 10−4 Torr, the films become amorphized TiO2 gradually, reaching an amorphous structure at 2.0 × 10−4 Torr (2.7 × 10−2 Pa). The films deposited above 0.5 × 10−4 Torr O2 show a comparable UV-induced hydrophilicity, and the amorphized TiO2 component in the films make their UV-induced hydrophilicity somewhat inferior to the well-crystallized anatase TiO2 film. [Copyright &y& Elsevier]

We characterize three as-deposited anatase TiO2 (a-TiO2) films with different deposition flux angles of 0°, 53°, and 86° tilted to Si <001> using thermoreflectance (TR) measurement in the temperature range between 30 and 300 K. The TR spectra at low temperature clearly show considerable difference in interband transitions of the tetragonal a-TiO2 with the largely top plane of {001} or the largely side planes of {100} and {010}. The indirect and direct interband transitions of the a-TiO2 are evaluated. The temperature dependences of the interband transition energies of the a-TiO2 are analyzed. The optical-axial anisotropy of the a-TiO2 films is discussed. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DES) consisting of EG-(ChCl: C 2 H 6 O 2) and TU-(ChCl: CH 4 N 2 S) assisted synthesized BiOCl/BiVO 4 heterostructured catalyst studied for electrochemical uric acid (UA) sensor and tetracycline photocatalytic degradation. The chemical composition of the BiOCl/BiVO 4 catalyst was analyzed by X-ray photoelectron spectroscopy (XPS). UV–vis spectroscopy reveals increased absorption of visible light till the near-infrared region, which results in a narrowing of band gap energy from 2.3 eV to 2.2 eV for BiOCl/BiVO 4 -TU. Morphology of catalyst analyzed using field-emission scanning electron microscope (FE-SEM) and Transmission electron microscope (TEM) technique. Time-Resolved photoluminescence (TRPL) confirms an increased lifetime of e−/h+ pair after heterostructure formation. The catalyst-modified glassy carbon electrode shows selectivity toward the detection of uric acid (UA). The limit of detection (LOD) is estimated to be 0.04688 μM for UA; also, interference and stability of catalyst were studied. Photocatalytic activity of the synthesized catalyst was investigated by degrading tetracycline (TC) antibiotic pollutants, and their intermediate product was analyzed by ion trap mass spectrometry (MS). [Display omitted] • BiOCl/BiVO 4 synthesis by deep eutectic solvents (DES). • TU-BiOCl/BiVO 4 catalyst electrochemically detects uric acid and tetracycline degradation. • Ion trap mass spectrometry reveals the degradation pathway of pollutants. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate highly stable inverted bulk heterojunction organic solar cells using aluminum-doped zinc oxide (AZO) as electron transport layers fabricated via a non-toxic so-gel process. The conductivity of the AZO layers can be enhanced fourfold as compared to that of intrinsic zinc oxide (ZnO) layers. The transmittance of AZO films is improved and the Haze value of the films is reduced by more than 50% in comparison to that of ZnO. The power conversion efficiency of the device reaches 6.51% and still has approximately 98% of the initial power conversion efficiency (PCE) after over 900 h without encapsulation. [ABSTRACT FROM AUTHOR]

Abstract: Niobium-doped titania (TNO) films of various Nb content were deposited on glass and silicon substrates by reactive co-sputtering of Ti and Nb metal targets. Nb content in the TNO films was varied from 0 to ∼13at.% (atomic percent), corresponding to Ti1−x Nb x O2 with x =0–0.52, by modulating the Nb target power from 0 to 150W (Watts). The influence of ion bombardment on the TNO films was investigated by applying an RF substrate bias from 0 to 25W. The as-deposited TNO films were all amorphous and insulating, but after annealing at 600°C for 1h in hydrogen, they became crystalline and conductive. The annealed films crystallized into either pure anatase or mixed anatase and rutile structures. The as-deposited and the annealed films were transparent, with an average transmittance above 70%. Anatase TNO film (Ti1−0.39Nb0.39O2) with Nb 9.7at.% exhibited a dramatically reduced resistivity of 9.2×10−4 Ωcm, a carrier density of 6.6×1021 cm−3 and a carrier mobility around 1.0cm2 V−1 s−1. In contrast, the mixed-phase Ti1−0.39Nb0.39O2 showed a higher resistivity of 1.2×10−1 Ωcm. This work demonstrates that the anatase phase, oxygen vacancies, and Nb dopants are all important factors in achieving high conductivities in TNO films. [Copyright &y& Elsevier]

Abstract: A series of sculptured porous nano-columnar titanium oxide films were prepared by glancing angle deposition (GLAD) method using an electron-beam evaporation system. The films were deposited on ITO glasses at various incident angles from 53° to 86°and used as photoanode in a dye-sensitized solar cell (DSSC). The as-deposited TiO2 films are comprised of helical nano-columns and assembled in an orderly manner with gaps or pores in between. The porous nanostructured films provide a synergetic effect of high surface area, effective route for electron transfer, tight interfaces, and enhanced light trapping, which are all beneficial for higher cell efficiency. The DSSCs incorporated with the GLAD films of 4μm thick exhibited a high fill factor (FF) up to 0.77. The TiO2 film deposited at an incident angle of 73° provides the largest internal surface area and the largest amount of dye absorption and results in the highest light conversion efficiency of 2.78%. [Copyright &y& Elsevier]

Abstract: Pure and carbon-doped amorphous titania films were prepared in an argon–oxygen plasma by reactive sputtering of a titanium metal target and co-sputtering of a Ti and a graphite target, respectively. The as-deposited films were subsequently annealed in vacuum and in air. The influence of the annealing atmosphere and temperature on the composition, phase transformation and crystallinity of the films was systematically studied. The results indicate that carbon incorporated in titania and an oxygen deficient environment both facilitate the formation of oxygen vacancies in titania which favors the phase transformation to rutile during annealing at low temperatures. A mechanism is proposed to explain why carbon incorporation and oxygen defects in titania favors the formation of rutile during annealing. [Copyright &y& Elsevier]

Abstract: A TiO2 thin film was deposited on AZ91 alloy to enhance the corrosion–resistance and photo-catalytic properties. Experimental results showed that the TiO2-coated AZ91 exhibited hydrophilicity. The corrosion potential of TiO2-deposited AZ91 was higher than that of the uncoated AZ91, suggesting an increase in the intrinsic corrosion resistance. Compared with the uncoated samples, the corrosion resistance of TiO2-deposited samples, on the other hand, deteriorated. FE-SEM observation showed polycrystalline characteristics as well as the presence of pinholes on the film. EDS analysis revealed the pinholes to be locales of incomplete deposition, where accelerated corrosion occurred. [Copyright &y& Elsevier]

Abstract: Carbon-doped or carbon-covered titania can enhance photocatalytic performance under visible light. Here we report the first instance of synergistic effect of the carbon incorporation in anatase titania (TiO2−x C x :C) films with both substitutional doping and surface covered characteristics, by reactively co-sputtering Ti metal and graphite targets. The nature of incorporated carbon is characterized by Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. The absorption edge of the carbon incorporated titania thin films shifted from ultraviolet to visible region and directly depended on the carbon content. The photocatalytic performance, e.g., photodegradation of methylene blue (MB), photo-reduction of silver-ions and super hydrophilicity, was greatly enhanced with increasing carbon content. The best photocatalytic activity is obtained in the TiO2−x C x :C film of the most carbon concentration about 9.3at.% with a degradation rate-constant of 0.108h−1 for MB under visible-light illumination. [Copyright &y& Elsevier]

Abstract: In the process of preparing a visible light photocatalyst CaIn2O4, a novel core shell like composite In2O3@CaIn2O4 was observed at intermediate calcination temperatures, during the solid-state reaction between ball milled powders of CaCO3 and In2O3. The composition, crystallinity and photo absorption of the coupled phases obtained in the temperature range 873–1323K, were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV–vis diffused reflectance spectroscopy. The coupled composite phases In2O3@CaIn2O4 showed superior visible light induced photocatalytic degradation of Methylene Blue (MB) compared to single phase CaIn2O4. Selective charge separation and efficient charge transport at the interface when illuminated are considered to be the possible reasons for the enhanced photocatalytic performance of this composite catalyst. [Copyright &y& Elsevier]

Abstract: Carbon-doped titanium oxide films (TiO x C y ) were deposited by an ion-assisted electron-beam evaporation system, using rutile TiO2 powder as the source material and carbon monoxide flowing through an ion gun as the dopant source. A series of films was prepared under the bombardment of ion beam with a fixed voltage of 1000 V and various beam currents of 10, 20 and 35 mA. As-deposited films have the primary structure of anatase TiO2, characterized by X-ray diffraction and Raman spectroscopy. With the increasing ion-beam current, the film crystallinity deteriorated, the concentration of carbon with Ti–C bonding in the films varied from 0.8 to 1.3 mol%, and their optical absorption edges gradually red-shifted from 370 to 410 nm. The TiO x C y film deposited with 10 mA beam current has well-crystallized anatase phase, exhibiting the highest water-contact angle reduction and the best visible-light photocatalytic activity. [Copyright &y& Elsevier]

Abstract: Boron nitride films on diamond buffer layers of varying grain size, surface roughness and crystallinity are deposited by the reaction of B2H6 and NH3 in a mixture of H2 and Ar via microwave plasma-assisted chemical vapor deposition. Various forms of boron nitride, including amorphous α-BN, hexagonal h-BN, turbostratic t-BN, rhombohedral r-BN, explosion E-BN, wurzitic w-BN and cubic c-BN, are detected in the BN films grown on different diamond buffer layers at varying distances from the interface of diamond and BN layers. The c-BN content in the BN films is inversely proportional to the surface roughness of the diamond buffer layers. Cubic boron nitride can directly grow on smooth nanocrystalline diamond films, while precursor layers consisting of various sp2-bonded BN phases are formed prior to the growth of c-BN film on rough microcrystalline diamond films. [Copyright &y& Elsevier]

Abstract: Nitrogen-doped titanium oxide (TiO x N y ) films were prepared with ion-assisted electron-beam evaporation. The nitrogen (N) incorporated in the film is influenced by the N2 flux modulated by the N2 flow rate through an ion gun. The TiO x N y films have the absorption edge of TiO2 red-shifted to 500nm and exhibit visible light-induced photocatalytic properties in the surface hydrophilicity and the degradation of methylene blue. The structures and states of nitrogen in the films are investigated by X-ray diffraction patterns (XRD), and X-ray photoelectron spectroscopy (XPS) and related to their visible light-induced photocatalytic properties. The results indicate that the substitutional N in anatase TiO2 can induce visible light photocatalysis. The substitutional N is readily doped by the energetic nitrogen ions from the ion gun. The best photocatalytic activity is obtained at the largest N loading about 5.6at.%, corresponding to the most substitutional N in anatase TiO2. The film exhibits the degradation of methylene blue with a rate-constant (k) about 0.065h−1 and retaining 7° water contact angle on the surface under visible light illumination. [Copyright &y& Elsevier]

Boron nitride films are produced by the reaction of diborane (B2H6) and ammonia (NH3) in a mixture of hydrogen and argon using microwave plasma-assisted chemical vapor deposition. Some parameters as NH3/B2H6 ratios, hydrogen addition, substrate-bias voltage and working pressure are modulated to obtain high c-BN content in the film. The influence of diamond films with various grain sizes as bufferlayer on the formation of c-BN is investigated. As-grown BN/diamond films are characterized by Fourier transform infrared spectra, X-ray diffraction patterns and scanning electron microscopy. The results indicate that the nature of diamond film affects the amount of c-BN in the BN layer. Nanocrystalline diamond film can promote the c-BN formation, resulting in the c-BN content up to 85%. Thick c-BN/diamond multilayer up to 5.5 μm in total thickness and with nearly pure c-BN content is synthesized. [Copyright &y& Elsevier]

Nanolaminates and bilayers of BN/AlN on Si were deposited using a reactive DC magnetron sputtering technique in a dual-cathode system. In the BN/AlN bilayers, there was little effect of the AlN thickness as a buffer layer on the crystallinity of the BN layer. A series of BN/AlN nanolaminates with periods (Λ) from 2.2 to 80 nm was produced by varying the rotation speed of the sample holder disc. At the periods thicker than 20 nm, the nanolaminates primarily consisted of sp3-bonded BN and w-AlN layers. For periods below 3.4 nm, the BN and AlN layers were intermixed and apparent wurtzite–AlBN phase was formed in the interfaces. Transparent and intact BN/AlN nanolaminates with thickness over 5 μm and with hardness over 33 GPa were obtained. The hardness of the nanolaminates was related to the structural characteristics obtained from XRD and FTIR results. [Copyright &y& Elsevier]