Advanced Materials Research Vols. 690-693

Abstract: Aluminum–induced crystallization of sputtered a-Si under two-step annealing procedure on glass substrate is studied. A 200 nm thick a-Si film was deposited by magnetron sputtering on glass and a Al film of 150 nm was sputtered on top. The samples were annealed under two-step annealing procedure. Nucleation and growth of grains were followed by optical microscopy (OM), X-ray diffraction (XRD), Raman spectroscopy, and energy dispersive spectroscopy (EDS). Continuous (111) oriented poly-Si films were obtained with a Raman Peak at 520.8cm^-1. The different annealing periods is discussed.

Abstract: The preparation and characterization of CuInS₂ thin films on ITO glass substrates prepared by one-step electrodeposition have been reported. Samples were characterized using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The results indicate that CuInS₂ is the major phase for the film deposited at -1.0 V, after annealing at 550°C in sulfur atmosphere, and the sample is Cu-rich and p-type semiconductor. Additionally, the energy band gap and carrier concentration for the sample were found to be 1.43 eV and 4.20×1017 cm−3, respectively. Furthermore, the maximum photocurrent density of the sample was found to be -1.15 mA/cm2 under 255 lx illumination, the sample shows the photo-enhancement effect.

Abstract: Dielectric barrier discharge (DBD) plasma was used to reduce copper oxide at atmospheric pressure using Ar and H₂ mixture gases. Effect of H₂ content on copper oxide reduction was investigated with a constant total flow rate of 100 mlmin^-1 when the discharge voltage was kept at 36 kV. The composition of the copper oxide samples before and after DBD plasma treatment was characterized by X-ray diffraction (XRD). The results showed that energetic electrons and metastable Ar were inefficient for reduction of copper oxide in this study and the highest copper oxide reduction rate was obtained when the H₂ content was 20%. In addition, no Cu₂O was observed. Optical emission spectra (OES) were observed during reduction of copper oxide at different H₂ contents, and the mechanism for copper oxide reduction using DBD discharge was discussed.

Abstract: Earth-abundant Cu₂ZnSnS₄(CZTS), a promising alternative photovoltaic material, was prepare by a mild solvothermal route and annealed. The as-prepared nanoparticles were obtained at 200°C and analyzed by X-ray diffraction(XRD). The crystallinity of CZTS particles was greatly improved by annealing in N2 gas shown in XRD. EDS results indicate the composition of the film and the variety of the ratio of the metal atoms and S atoms.

Abstract: Polycrystalline mercuric iodide films are being developed as a new detector technology for digital X-ray imaging. The properties of the contact between electrode and film play an important role in the performance of the polycrystalline mercuric iodide detector. In this paper, the films were grown on the thin film transistor (TFT) substrates via hot-wall physical vapor deposition method. Au front contacts were deposited onto the HgI2 films by thermal evaporation under a vacuum of 10-4Pa. The HgI2 films were characterized by X-ray diffraction (XRD). The surface morphology of the films before and after the process of evaporating Au was compared by scan electron microscopes (SEM). And the I-V curve was measured after evaporating Au electrode. The results indicate that the polycrystalline mercuric iodide films we prepared have a very strong (001) growth-preference. Au was deposited on the grain surface forming excellent ohmic contact with polycrystalline α-HgI2 film which was also confirmed by the I-V characteristic of HgI2 film after the process of evaporating Au electrode.

Abstract: TiO2 composite photocatalytic film was prepared on steel by plasma electrolytic oxidation in aluminate electrolyte. The microstructure of the composite film was investigated by XRD and SEM. The photocatalytic properties of the films treated with different time were studied by photocatalytic degradation of Rhodamine B with various irradiation time. The results revealed that the as prepared film was composed of crystal phase of much A-TiO2 and a little γ-Al2O3. The film surface was rough and porous. The pores are in the dimensions of 2-8 μm. The photocatalytic experimental results showed that for the same irradiation time, the removal ratio of Rhodamine B of the films gradually increased with increasing the treating time. For each film, the removal ratio of Rhodamine B of the film also gradually increased when increase the irradiation time. The 30 min treated sample exhibited a removal ratio of 80% in 2h irradiation of ultraviolet light.

Abstract: WO₃ nano-films were deposited on Al₂O₃ substrate by dc reactive magnetron sputtering method. The effects of preparing conditions, such as the discharge gas ratio (Ar:O2), working pressure, sputtering time and annealing temperature on microstructure, crystalline state and NO2-sensing properties of WO₃ nano-films were investigated by orthogonal trial experiment method. The optimum technological conditions were determined by orthogonal test and extreme difference analysis. The crystallization, morphology and composition of WO₃ thin film obtained at the optimal parameters were studied by XRD, SEM and XPS. The gas sensing mechanism was also studied. WO₃ nano-film shows high sensitivity, fast response, good selectivity at the best operating temperature 200°C.

Abstract: Nickel oxide (NiO) thin films were deposited on ITO/glass substrates by radio frequency magnetron sputtering. The electrochromic property of NiO films was investigated using cyclic voltammograms (CV), performed on NiO films immersed in an electrolyte of 1 M LiClO₄ in propylene carbonate (PC). Optical, electrochemical and structural properties of the films, as a function of coloration–bleaching cycle, were characterized using an UV-Vis-NIR spectrophotometer, cyclic voltammetry (CV), X-ray diffraction(XRD) and a field emission scanning electron microscope (FE-SEM). The optimal electrochromic NiO film, with a thickness of 180 nm, exhibits a maximum transmittance variation (ΔT%) of 53.97 %, an optical density change (ΔOD) of 0.66, an intercalation charge (Q) of 14.65 mC/cm², and a coloration efficiency (η) of 44.85 cm²/C between the colored and bleached states at a wavelength (λ) of 550 nm.

Abstract: A series of Mg thin films with different thickness from 10 nm to 200 nm were prepared and hydrogenated. The transmission spectrum and sheet resistance before and after hydrogenation were measured. The transmission increased from nearly zero to 16 %, the maximal changes happened at 561 nm was 17.6% with 50 nm thickness of Mg thin film, and its sheet resistance increased from 2.3 to 75.2Ω/. The results show that the Mg thin films changed obviously from shiny, metallic films to transparent, insulating films. The attractive phenomenon might enlighten the investigation and be of particular interest for switchable mirrors.

Abstract: W-doped Vanadium oxide thin films were prepared on the substrates of SiO₂ glass, float glass and Si (100) by reactive magnetron sputtering after annealing in vacuum. The structure, morphology and phase transition were characterized by X-ray diffractometer, atomic force microscopy (AFM) and differential thermal analysis (DTA), respectively. The results show that, the major phase of W-doped films on SiO₂ glass is VO₂.Dopant reduce the phase transition temperature of VO₂ thin films to 21.9°C. The root-mean-square roughness of the film increase for the longer deposition time.