Negative-differential-resistance effects in amorphous CuInS2 thin film

The microstructure and the optical properties of amorphous CuInS₂ thin films deposited on glass substrates by a single source thermal evaporation technique, are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission and reflection measurements. Amorphous CuInS₂ thin films sandwiched between gold and copper electrodes, show current-controlled electronic switching. The switching is believed to be associated rather with electronic processes than the thermal ones.     

Computer simulation of the formation of niobium film nanostructure by low-temperature deposition

Computer simulation is explored to study the formation of the niobium film nanostructure by low-temperature deposition. The dependence of dynamical evolution of surface morphology with respect to film thickness is investigated. Calculations of the film density variation at 300 and 800 K are performed. It has been established that the formation of the microcracks elongated along the crystallographic 〈1 0 0〉 direction was the result of surface instabilities during film growth. The internal microstresses arising in the films were evaluated. It has become apparent that the whole complex of phenomena: the porosity formations, the block structure development, the internal microstresses, taking place in the low-temperature deposition, are involved in surface instabilities during niobium film growth.     

Graphite formation on Ni film by chemical vapor deposition

Thin film formation of graphite by chemical vapor deposition using 2-methyl-1,2′-naphthyl ketone as a starting material was carried out on Ni film substrates. On Ni films directly deposited on quartz glass, the graphite films were obtained when the Ni film thickness was above 1 000 Å and above 5 000 Å at 700 °C and 1 000 °C, respectively. Depositions on thinner Ni film substrates comprise amorphous carbon (a-C) or graphite tubes which was owing to the thermal coagulation of the Ni film into droplets. On the other hand, graphite film was obtained on the Ni film with thickness 10 Å when a-C was inserted between the Ni film and the quartz glass. The coagulation of the Ni film is considered to be avoided by inserting a-C layer.     

Shallow bath chemical deposition of CdS thin film

Cadmium sulfide thin film was grown by shallow chemical bath deposition technique. This technique used a highly conducted hot plate to heat the substrate, while using a shallow bath for higher thermal gradients. As a result, large area uniformity could be achieved and the homogeneous nucleation was suppressed. More importantly, the solution used was greatly reduced, which is crucial for cost reduction in practice. The effects of temperature and shaking on the growth kinetics and film properties were investigated. The reaction activation energy was obtained to be 0.84 eV, and was not affected much by shaking indicating that the deposition is essentially reaction controlled. Furthermore, the films deposited at low or high temperature conditions had better photoconductivity.     

Preparation of TiO2 thick film by laser chemical vapor deposition method

A TiO₂ film was prepared on Pt/Ti/SiO₂/Si substrate by a laser chemical vapor deposition method. The rutile TiO₂ film with pyramidal grains and columnar cross-section was obtained at a high deposition rate (R _dep = 11.4 μm h^?1). At 300 K and 1 MHz, the dielectric constant (ε _r) and loss (tanδ) of the TiO₂ film were about 73.0 and 0.0069, respectively. The electrical properties of TiO₂ film were investigated by ac impedance spectroscopy over ranges of temperature (300–873 K) and frequency (10²–10⁷ Hz). The Cole–Cole plots between real and imaginary parts of the impedance (Z′ and Z′′) in the above frequency and temperature range suggested the presence of two relaxation regimes that were attributed to grain and grain boundary responses. The ionic conduction in the rutile TiO₂ film was dominated by the oxygen vacancies.     

CuInS2薄膜的单源热蒸发制备及其性能研究

本文以烧结合成的CuInS2粉末为原料,采用单源热蒸发技术在玻璃基底上沉积CuInS2薄膜。随着退火温度的升高,薄膜的结晶性能增强,表现出高度的(112)晶面择优取向,SEM观察显示:350℃退火后,薄膜致密,晶粒细小,大小为数十纳米。同时,热探针测试发现:薄膜的导电类型为弱N型。光学性能方面,当退火温度高于250℃时,CuInS2薄膜的禁带宽度为1.50 eV,接近吸收太阳光谱所需的理想禁带宽度值。     

微波辅助化学浴沉积CdS薄膜

采用微波辅助化学浴沉积法快速制备了硫化镉薄膜(CdS),并对薄膜进行了X射线衍射(XRD)、紫外透射和吸收光谱的测试和分析.利用测试结果计算CdS薄膜的带隙宽度与以往结果相同.由于传统制备方法中热量从外向内传播,而微波有很强的穿透能力可在很短时间内均匀加热,所以此种方法制得的CdS薄膜质量较好,沉积速度明显提高.     

单源共蒸法制备CuInS2薄膜及特性分析

将单质Cu、In和S粉末按一定比例均匀混合,单源共蒸发沉积CuInS2薄膜.氮气保护对薄膜进行热处理.研究不同热处理条件对薄膜表面形貌、化学组分及电学特性的影响.XRD分析给出直接沉积的CuInS2薄膜为黄铜矿结构,整体性能较差.经400℃、20 min热处理后,CuInS2薄膜特性得到明显的改善,导电类型呈P型,体内元素化学计量比Cu:In:S=1:0.9:1.5接近标准值,Cu含量略多,电阻率为4.8× 10-2 Ω·cm,薄膜的直接光学带隙1.42 eV,光吸收系数105 cm-1.440℃、10 min热处理的薄膜,晶相结构没变但导电类型转为N型,元素化学计量比Cu:In:S=1:2.3:0.8,In元素过量,电阻率为1.3×10-2 Ω ·cm,光吸收系数104 cm-1,直接光学带隙1.39 eV.     

SiOx plasma thin film deposition using a low-temperature cascade arc torch

Plasma thin films were deposited from gas mixtures of hexamethyldisiloxane (HMDSO) and oxygen (O₂) using a low-temperature cascade arc torch (LTCAT). Various properties of the deposited HMDSO plasma coatings, including refractive index (RI), surface contact angle, and hardness were evaluated. The characterization results using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, ellipsometry, and water contact angle measurements indicated that, with increased O₂ addition, the deposited HMDSO plasma thin films were of inorganic SiO_x nature. It was also found that, in the LTCAT plasma system, O₂ addition significantly improves the hardness of the resulting HMDSO plasma coatings. The film hardness of the deposited HMDSO plasma coatings measured by a standard pencil test (ASTM D3363-05) reached 6H with increased O₂ addition in the HMDSO/O₂ gas mixture. Such hard plasma coatings could be potentially used for many important industrial applications, such as anti-scratch coatings on plastic glasses and various plastic lens materials.     

Optimization of deposition temperature of SILAR Cu-rich CuInS2 thin films

CuInS₂ (CIS) is studied widely as a promising absorber material for high efficient and low cost thin film solar cells. CIS thin films are prepared on soda lime glass substrates using Successive Ionic Layer Adsorption and Reaction (SILAR) technique at different deposition temperatures (40 to 70 °C). The structural, compositional and optical properties are studied with x-ray diffractometer, energy dispersive x-ray analyzer and spectrophotometer. The influence of the deposition temperature on the properties of CIS thin films is discussed in this paper in detail.     

锐钛矿型TiO2薄膜的低温制备及性能研究

采用液相沉积法,在低温下制备TiO2薄膜,研究了制备条件对薄膜中TiO2的晶型、薄膜厚度、透光性、亲水性及光催化活性的影响.结果表明,在90℃下制备的TiO2为锐钛矿型,薄膜的厚度与反应温度、沉积时间、HBO3的加入量及反应物浓度有关,所制备的薄膜具有良好的光诱导超亲水特性和光催化活性,在可见光区的透光率＞80%.     

Optimization of a MoSe2 thin film deposition technique

MoSe₂ thin films deposited by DC diode sputtering have been investigated by scanning electron microscopy, electron microprobe analysis X ray analysis optical absorption and electron spectroscopy (XPS).It has been found that stoichiometric thin films are obtained after appropriate annealing for any kind of substrate. Thin films crystallize in the hexagonal structure The optical gaps and the chemical shifts of the XPS lines show that thin films are composed of good MoSe₂ crystallites     

Fabrication and characterization of CuInS2 films by chemical bath deposition in acid conditions

Non-crystalline copper indium disulphide (CuInS₂) thin films had been deposited on ITO glass by chemical bath deposition (CBD) in acid conditions. Then polycrystalline CuInS₂ films were obtained after sulfuration in sulfur atmosphere at 450 °C for 1.5 h. The films had been characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), Raman scattering measurements and energy dispersive X-ray analysis (EDX). The optical and electrical property of the thin films was also measured. The results showed that the pure, flatness, and well crystallized CuInS₂ thin films with good electrical and optical property had been obtained, meaning that the chemical bath deposition in acid conditions is suitable for the deposition of CuInS₂ thin films.     

Transparent conducting indium oxide thin films grown by low-temperature metal organic chemical vapor deposition

We have grown indium oxide thin films on silicon substrates at low temperature by metal organic chemical vapor deposition. Polycrystalline film growth could only be obtained at temperatures below 400 °C. Above 400 °C, metallic indium deposition dominated. We have investigated the effect of substrate temperature and reactor pressure on the film growth and structural properties in the range of 250-350 °C and 5 ^? 10³-4 ^? 10⁴ Pa. The film grown at 300 °C exhibited a resistivity of about 3.6 × 10^− 3 Ω cm and a maximal optical transmittance of more than 95% in the visible range. The film showed an optical band gap of about 3.6 eV.     

Polycrystalline Si1-x Ge x thin film deposition by rapid thermal chemical vapor deposition

Polycrystalline silicon germanium (poly-Si_1−xGe_x) thin films on a-Si film have been deposited by rapid thermal chemical vapor deposition (RTCVD) with SiH₄–GeH₄–H₂. Effect of GeH₄/SiH₄ and deposition temperature on stoichiometry (x), Si-Ge binding character, composition, hydrogen configuration, crystallinity, preferred orientation, grain size, and surface roughness of poly-Si_1−xGe_x films has been investigated. Poly-Si_1−xGe_x deposited on the substrate with amorphous silicon buffer layer on oxide shows better crystallinity and contains the less amount of oxygen than the one deposited directly on the oxide surface. At low temperature region, the Ge–H bond with the small amount of Si–H₂ bond is dominant but all hydrogen bonds are desorbed at high temperature. All films have polycrystalline phase and the grain size and (111) orientation increased with increasing deposition temperature in which Ge content also increases at the fixed gas flow rate of GeH₄ to total source gas. Poly-Si_1−xGe_x/Si thin film transistors (TFT) are fabricated and hydrogen during post-hydrogenation process preferentially is attached to Ge dangling bond and the TFT characteristics could be improved.     

新型纳米TiO2膜电极的制备及应用研究

采用常压金属有机物化学气相沉积技术在钛板上沉积了TiO2膜电极,研究了其制备的重要工艺参数,进行了光化学、电化学特性的测试和表征,并应用于典型有机污染物苯酚的光电催化降解研究.结果表明,沉积温度是影响TiO2膜电极制备的重要因素.XRD图谱表明,沉积温度为500℃时负载的TiO3晶型结构为锐钛矿,600℃时出现金红石相.光电流测试表明,500℃时制备的TiO2膜的光电流最佳.以苯酚为污染物进行了光电催化降解实验,结果表明,其光电催化效果高于光催化、电催化降解效果,显示了较好的废水处理应用前景.