硅在cBN单晶合成中的行为

 实验制备了复合氮化物Li₈SiN₄，并对合成温度、合成时间、气流量等因素的影响以及产物的稳定性进行了讨论。研究了Li₈SiN₄作为触媒添加剂时硅在cBN单晶合成中的作用。结果表明：cBN晶体多为截角八面体，晶面致密光滑；硅参与cBN的合成反应，并以SiO₂的形式沉积在cBN表面。     

MOCVD制备InxGa1－xN/GaN MQWs的温度依赖性

利用方势阱模型对In_xGa_1－xN/GaN MQWs结构的光特性进行了量子力学定性理论分析.并在MO源流量恒定条件下，在570℃～640℃范围内进行了不同生长温度的多量子阱制备实验，对In_xGa_1－xN制备过程中的In组份掺入效率的温度依赖关系进行研究.通过对制备样品的PL谱测量分析，得到了587℃～600℃的In组份最佳掺入温度区间.     

射频磁控反应溅射氮氧化硅薄膜的研究

利用SiOxNy薄膜光学常数随化学计量比连续变化的特性,给出了制备折射率连续可调的SiOxNy薄膜的实验条件。用磁控反应溅射法制备了不同氮氧比的SiOxNy薄膜。研究了不同气流比率条件下薄膜光学常数、化学成分及溅射速率等的变化。用UV-VIS光谱仪测试了透射率曲线,利用改进的单纯型法拟合透射率曲线计算得到了折射率和消光系数。测试了红外傅立叶光谱(FTIR)曲线和X光光电子能谱(XPS)分析了薄膜成分的变化。实验表明薄膜特性与N2／O2流量比率密切相关,通过控制总压和改变气体流量比可控制SiOxNy薄膜的折射率n从1．92到1．46连续变化,应用Wemple-DiDomenico模型计算出光子带隙在6．5eV到5eV之间单调变化。     

热电材料PbTe1-xSex的高压制备及电学性能研究

 利用高温高压技术,制备了热电材料PbTe和PbSe的固溶体合金PbTe_1-xSe_x,在室温下对其结构及电学性质进行了研究。X射线衍射（XRD）测试结果表明：PbTe_1-xSe_x具有NaCl结构;晶格常数随着Se含量（x）的增加而减小;PbTe_1-xSe_x的电阻率和Seebeck系数的绝对值随x的增大而减小;功率因子随x的增大先增大而后减小,当x=0.1时功率因子最高,达到21.7 μW/(cm·K²),比相同条件下制备的PbTe高20%。     

TiO2纳米薄膜微观结构及光学性能研究

用sol-gel法制备了纳米TiO₂薄膜,用原子力显微镜(AFM)观察了薄膜的表面形貌,测量了薄膜的表面粗糙度(RMS)为2.832 nm;用红外光谱(IR)研究了TiO₂薄膜前驱体溶胶的组成; 探讨了TiO₂薄膜的焙烧温度、层数等制备条件对TiO2光催化活性的影响,结果发现在490℃,8层膜的TiO₂活性最高.     

直流磁控溅射Cr-Cr2O3复合金属陶瓷薄膜光学特性研究

采用直流反应磁控溅射技术在不同靶电流条件下制备了Cr-Cr₂O₃金属陶瓷薄膜，并利用椭偏仪测量了薄膜的光学常数。采用修正的 M-G (Maxwell-Gannett)理论对不同靶电流条件下沉积的Cr-Cr₂O₃金属陶瓷薄膜的光学常数进行了理论计算，并将理论计算结果与实验数据进行了比较。结果表明：随着靶电流的增加，膜层中金属微粒体积百分比增加，金属微粒的平均半径随之增加，且金属微粒逐渐趋于扁圆形，理论计算结果与实验结果吻合较好。     

基于等离子体增强化学气相沉积技术的光电子器件多层抗反膜的设计和制作

针对光电子器件端面抗反镀膜的要求,研究了基于等离子体增强化学气相沉积(PECVD)技术的多层抗反膜的设计和制作.首先,对影响SiN_x折射率的因素进行了实验研究,确定了具有大折射率差的SiO₂/SiN_x材料的PECVD沉积条件.根据理论计算分析,设计了四层SiO₂/SiN_x抗反膜结构,能够在70 nm的波长范围内实现低于10^-4的反射率     

高压下FexN化合物的相分解

 本文研究了室温下压力对Fe_xN化合物相分解的影响。X射线衍射分析表明，高压促使氮原子从Fe_xN化合物的晶格中脱溶出来，引起相分解，形成母相与α-Fe。这种相分解现象随压力增大而加强。通过分析不同压力下母相Fe_xN与α-Fe的相对含量，研究了氮从Fe_xN中脱溶的动力学过程，并计算出激活体积。对于Fe₃N和Fe₄N化合物，其激活体积分别为2.24×10^-5 m³/mol和1.62×10^-5 m³/mol。本实验还指出，通过对Fe_xN化合物的高压处理以及适当条件下退火，可以获得Fe₁₆N₂化合物。     

高能核–核碰撞Drell–Yan过程K因子常数性的研究

在高能核–核碰撞Drell-Yan过程考虑湮没项和康普顿散射项的基础上,利用双重Q²重标度模型,分别计算了碳、钙、铁、锡与其自身的核–核碰撞.结果表明,对于不同的x₁值,K因子随x₂的变化很不相同;同时,K因子变化的幅度是随核素A不同而发生微弱变化的,在特定的x₁,x₂取值有限范围内它不能近似取为常数.计算结果与实验的对比是对所用模型及QCD理论适用性的一种检验.     

Xc辐射衰变和新粒子强产生

本文考虑了x_c粒子的强产生及其辐射衰变,指出J/ψ粒子的强产生应包括这部分贡献.结果,合理地缩小了 J/ψ,粒子和ψ′粒子同层子的有效耦合常数之间的差距,保留了以前工作中的主要结果,得到了不同质心系总能量下四种过程通过 x_c 的产生及其辐射衰交产生 J/ψ粒子的微分截面在 J/ψ粒子产生总微分截面中所占的比例.最后,对本文所用模型和胶子聚合模型作了简单比较.     

微晶硅薄膜高速沉积及电学性质的研究

采用甚高频等离子体增强化学气相沉积（VHF-PECVD）技术在高功率密度和高压强条件下,通过改变硅烷浓度和气体总流量对薄膜沉积参数进行了两因素优化,最终在硅烷浓度为45%,气体总流量为100 sccm条件下,获得沉积速率142 nm/s,电导激活能047 eV的优质硅薄膜;同时,通过单因素优化制备出沉积速率为21 nm/s的微晶硅薄膜.利用晶粒间界势垒模型和费米能级统计偏移模型对薄膜的电学特性和传导行为分别进行了研究分析,同时初步分析了“后氧化”对薄膜电学性能的影响. 关键词： μc-Si:H 甚高频等离子体增强化学气相沉积 高速沉积 电学特性     

Pulsed laser deposition of (110) oriented semiconductive SrFeO3−x thin films

 The semiconductive perovskite-type oxide SrFeO_3-x (x<0.16) (SFO) thin films have been directly fabricated on (001)SrTiO₃ and (001)LaAlO₃ single crystal substrates by pulsed laser deposition(PLD) under high oxygen partial pressure of 100 Pa. The SFO thin films were (110) oriented. The x-ray photoelectron spectroscopy (XPS) analysis showed that the surface of SFO thin film has strong gas absorption capability. The resistance versus temperature has been measured in the temperature range from 77 K to 300 K. The SFO thin film showed typical semiconductive property. Dependence of resistance of SFO thin film on oxygen pressure was measured and result showed that the SFO thin film had better oxygen sensitive property. Received: 14 May 1996/Accepted: 15 August 1996     

GaP薄膜的射频磁控溅射沉积及其计算机模拟

以GaP为靶材采用射频磁控溅射法制备GaP红外光学薄膜，通过保持Ar Ⅰ 750nm发射光谱线强度不变获得了不同工艺参数，并对沉积过程进行了计算机模拟.功率较小、气压较大时，Ga和P的溅射率、输运效率及沉积到衬底时的能量均较小，Ga的溅射率及输运效率均大于P的，使薄膜沉积速率较低、薄膜中Ga的含量大于P的，GaP薄膜产生较大吸收.功率较大、气压较小时，Ga和P的溅射率、输运效率及沉积到衬底时的能量均增大，Ga的溅射率大于P的、但其输运效率小于P的，使GaP薄膜的沉积速率增大、薄膜中Ga与P的含量接近化学计量比，GaP薄膜的吸收降低，因此有利于制备厚度较大的GaP薄膜. 关键词： GaP 薄膜 射频磁控溅射 计算机模拟     

Deposition of Ag nanostructures on TiO2 thin films by RF magnetron sputtering

Ag nanostructures on TiO₂ films were deposited by RF magnetron sputtering under variable deposition parameters, such as DC potential, RF-power and total pressure. The concentration, shape, and distribution of the deposited nanostructures and continuous Ag films on thin films of TiO₂ can be tailored by careful variation of the deposition parameters. Controllable clusterlike, islandlike and film Ag structures on TiO₂ film were obtained, respectively. DC potential was found as an appropriate parameter to tailor the change of Ag nanostructure and the overall Ag amount. The compositions, nanostructures and morphologies of nanocomposite films appreciably influence the optical response.     

Photocatalytic activity of dc magnetron sputter deposited amorphous TiO2 thin films

For photocatalytic thin film applications TiO₂ is one of the most important materials. The most studied TiO₂ crystal phase is anatase, though also rutile and brookite show good photoactivity. Usually anatase or a mixture of rutile and anatase is applied for powder or thin film catalysts. It has been claimed that amorphous films do not exhibit any or only a very low photocatalytic activity.We have deposited amorphous thin films by dc magnetron sputtering from sub-stoichiometric TiO_2−x targets. The coatings are transparent and show a photocatalytic activity half of that of a thin layer of spin-coated reference photocatalyst powder. Annealing the thin films to yield anatase crystallization more than doubles their photocatalytic activity. At the same film thickness these thin films show the same activity as a commercially available photocatalytic coating.The dependence of the photocatalytic activity on deposition parameters like gas pressure and sputter power is discussed. A decrease in film density, as deduced from the refractive index and the microstructure, resulted in an increase in photocatalytic activity. Film thickness has a marked influence on the photocatalytic activity, showing a strong increase up to 300-400 nm, followed by a much shallower slope.     

Optimization of process parameters of titanium dioxide films by response surfaces methodology

An efficient approach for determination of the optimum process parameters for titanium dioxide coatings by using second-order response surface model is presented and investigated experimentally. Thin films were prepared by electron-beam evaporation associated with ion-beam assisted deposition by using different control factors, including starting materials, working pressure, substrate temperature, deposition rate and annealing temperature. The factorial design of the experiment was established to meet the equipment conditions and to avoid affecting the results. The main effect between various factors and interactions are independent. The significant level of both the main effects and the interaction are observed by analysis of variance (ANOVA) approach. Based on the statistical analysis, the results have provided much valuable information on the relationship between various control factors and thin film properties. Besides the optimum optical constants and surface roughness of TiO₂ thin films were obtained in the range of each parameter level. The factorial prediction model for preparation parameters of thin film was also established.     

Optimum packing density and crystal structure of tin-doped indium oxide thin films for high-temperature annealing processes

The influence of high-temperature annealing on the electrical properties and microstructure of tin-doped indium oxide (ITO) thin films was investigated as a function of oxygen gas flow ratio to argon gas during the sputtering deposition. The ITO thin films were annealed at 500 °C in air after the deposition. It was found that the ITO thin films, which were deposited in relatively low oxygen gas flow ratio, exhibited high Hall mobility and low-resistivity after the annealing. Furthermore, the X-ray reflectivity and diffraction measurement revealed that the ITO thin film with low-resistivity after annealing exhibited high packing density, smooth surface and low crystallization degree. It can be considered that the carrier electron scattering was suppressed with increasing in the packing density of the ITO thin film; as a result, the Hall mobility and resistivity were improved.     

Effect of argon ion activity on the properties of Y2O3 thin films deposited by low pressure PACVD

Yttrium oxide thin films are deposited by microwave electron cyclotron resonance (ECR) plasma assisted metal organic chemical vapour deposition process using an indegeneously developed Y(thd)₃ {(2,2,6,6-tetramethyl-3,5-heptanedionate)yttrium} precursor. Depositions were carried out at two different argon gas flow rates keeping precursor and oxygen gas flow rate constant. The deposited coatings are characterized by X-ray photoelectron spectroscopy (XPS), glancing angle X-ray diffraction (GIXRD) and infrared spectroscopy. Optical properties of the films are studied by spectroscopic ellipsometry. Hardness and elastic modulus of the films are measured by load depth sensing nanoindentation technique. Stability of the film and its adhesion with the substrate is inferred from the nanoscratch test.It is shown here that, the change in the argon gas flow rates changes the ionization of the gas in the microwave ECR plasma and imposes a drastic change in the characteristics like composition, structure as well as mechanical properties of the deposited film.