Fe和Fe3O4硫化制备的FeS2薄膜的性能

用溅射Fe和电沉积Fe3O4先驱体硫化制备出FeS2薄膜,研究了不同先驱体对硫化过程和FeS2薄膜性能的影响．结果表明,两种先驱体结晶成的FeS2能够在一定程度上保留先驱体形貌特征．Fe生成FeS2的热力学驱动力比较高,虽然可能生成FeS的过渡相;Fe硫化生成的薄膜平整致密,晶粒生长比较充分,尺寸较大,其禁带宽度接近理论值．Fe3O4硫化生成FeS2的热力学驱动力较低,生成的薄膜表面疏松多孔,晶粒细小;薄膜的晶界等面缺陷比例较大和几何连续性较低使其电阻率较高、禁带宽度和载流子迁移率低于Fe膜硫化FeS2薄膜．     

硫化压力对电沉积并硫化合成的FeS2薄膜组织结构的影响

采用电沉积及400℃不同压力硫化热处理制备了多晶FeS2薄膜,研究了硫化压力对薄膜晶体结构及微观组织的影响。在较低的硫化压力条件下,电沉积得到的Fe3O4先驱体硫化反应不充分,薄膜组织中FeS2与Fe3O4共存。当硫化压力高于20kPa时,Fe3O4先驱体可充分地转变成具有细小晶粒形态的FeS2,薄膜形貌也由多孔疏松演变为均匀平整。硫化压力在5～40kPa范围内变化对FeS2晶粒尺寸影响不明显,但使FeS2晶格常数略有下降。     

薄膜生长基底对FeS2晶体取向的影响

用Fe膜硫化法制备了FeS2薄膜,分析了基底对FeS2薄膜晶体结构和位向分布的影响.结果表明,改变基底晶体的类型能够在一定程度上控制FeS2薄膜的晶体位向分布.FeS2薄膜在Si(100)、Si(111)和Al基底上可获得(200)方向的择优取向,在TiO2基底上可同时获得(200)及(220)择优取向,非晶玻璃基底对位向分布影响不明显.不同的基底与Fe薄膜的界面错配度不同,可改变薄膜晶体位向的分布,导致晶格畸变程度和晶粒尺寸的变化.当基底为非晶结构或界面的错配度较大时,FeS2晶体的取向分布主要受表面能和晶粒优先生长方向的控制,薄膜具有较小的晶格畸变和较细的晶粒;当基底为晶态并且界面错配度较小时,FeS2晶体取向的分布除受表面能及晶粒优先生长方向控制外,还受界面应变能的控制,此时薄膜易形成较大的晶格畸变和粗晶粒.     

硫化时间对电沉积制备FeS2薄膜组织与结构的影响

利用电沉积及热硫化法制备了FeS2 多晶薄膜,研究了不同硫化时间对FeS2 薄膜形成过程的影响。结果表明采用Na2S2O3 和FeSO4 水溶液电沉积和150~ 200℃处理可以制备多孔Fe3O4 薄膜,再经400℃、80kPa硫化处理,Fe3O4 可转变成FeS2 多晶薄膜。随硫化时间延长到10h,FeS2 的晶格常数减小而晶粒粗化,再继续延长硫化时间,FeS2 的晶格常数增大而晶粒尺寸下降。可以用点缺陷浓度、相变应力及亚晶界运动等因素分析Fe3O4 向FeS2 转变过程中的微观组织参数变化规律。     

晶体面缺陷对FeS2薄膜电学性能的影响

采用Fe膜热硫化技术制备了具有不同比表面积和比晶界面积的FeS2薄膜,并测定其载流子浓度和电阻率,研究了FeS2薄膜表面和晶界等面缺陷对FeS2薄膜电学性能的影响.结果表明,表面和晶界两种面缺陷对FeS2薄膜的电学性能有类似的影响规律.在一定范围内,随着薄膜比表面积和比晶界面积的增大,载流子浓度提高而电阻率下降.面缺陷数量的变化可导致FeS2晶体中点缺陷数量、禁带中缺陷能级密度、不充分相变产物比例和相变应力水平的变化,从而导致载流子浓度和电阻率的变化.     

铜薄膜微结构的X射线衍射线形分析

首先采用真空蒸镀法制备了不同厚度的铜薄膜,并对薄膜进行了退火处理;然后用X射线衍射仪测定铜薄膜的衍射谱,最后采用线形分析法对衍射谱进行计算,得到了不同厚度铜薄膜退火前后的晶粒尺寸和微应变。结果表明:真空蒸镀铜薄膜晶粒尺寸随薄膜厚度的增加而增大,微应变随薄膜厚度的增加而减小;退火处理后薄膜晶粒明显长大,薄膜微应变在退火处理后明显减小。     

电沉积FeS2(Pyrite)薄膜的制备与性能研究

采用含铁和硫元素的水溶液电沉积制备了FeS2 薄膜,并在硫氛围中退火获得样品。研究了样品的微结构和光吸收以及电学性质。结果表明薄膜样品晶相单一,晶粒尺寸约为100nm,光吸收系数随沉积时间增加略有增大,电阻率随薄膜沉积时间的增加而减小。为防止薄膜脱落,在沉积过程中使用了阳离子表面活性剂,得到了均匀且粘附性较强的膜。     

金属氧化物半导体薄膜气敏机理研究进展

气体传感器的核心介质为气敏薄膜,而薄膜本身的特性有关键的影响,主要体现在薄膜微观结构如晶粒尺寸、膜厚、空隙率和有效表面积等方面。溶胶-凝胶法由于有方法简单及成膜温度低等优点,得到了广泛研究与应用。本文综述了溶胶-凝胶法制备的金属氧化物薄膜微纳结构与气敏机理进来的研究进展,结果表明最佳的晶粒尺寸约为10nm,最佳膜厚约为110 nm。在晶粒尺寸控制方面,通过控制煅烧温度与时间及在溶胶-凝胶过程中加入不同的添加剂,可有效优化晶粒尺寸提高灵敏度。最后,从能带结构角度总结了气敏传感器的电学特性及荷电传输机理,讨论了热电子发射理论和电子隧穿理论起主导作用时的薄膜微纳结构。     

Fe的硫化物与TiO2复合薄膜的制备、结构与性质

用溶胶凝胶法制备了TiO2薄膜，用热分解Fe[CS(NH2)2]^2 法在TiO2薄膜表面制备了铁硫化合物颗粒。用XRD、SEM、TEM、EDS研究了退火温度、退火时间、初始溶液浓度、成膜厚度对铁硫化合物相组成与形貌的影响。结果表明。在550℃下退火的薄膜中。铁硫化合物以纯黄铁矿相(FeS2)存在。在400℃退火的薄膜中。Fe[CS(NH2)2]^2 首先分解成复硫铁矿(Fe3S4)．随着退火时间的增加逐渐转变成黄铁矿相与磁黄铁矿相(Fe1-xS)。TiO2膜是一层多孔膜。铁硫化合物覆盖在TiO2表面．颗粒尺寸随着初始溶液浓度减小从几个微米减小到十几个纳米；增加成膜厚度、退火时间，会使铁硫化合物的形貌按颗粒→岛(直径超过5μm的团聚物)一层的趋势变化。样品在可见光区光吸收率随着初始溶液浓度、退火时间、成膜厚度的增加而增加。     

氮气流量对CuInS2薄膜微结构的影响

采用硫化法制备出具有多晶结构的光吸收层CuInS2薄膜，研究了硫源处N2流量对CuInS2薄膜微结构的影响。利用SEM和EDS观察和分析了它们的表面形貌和成分，采用XRD表征了薄膜的结构。结果表明：N2流量增大到600ml／min制得具有黄铜矿结构且沿（112）晶向择优生长的CuInS2薄膜，晶粒尺寸为230nm。     

Impact of thickness on vacuum deposited PbSe thin films

Lead Selenide thin films were prepared by vacuum evaporation technique with different thickness ranges from 50 to 200 nm on glass substrates. The structural studies revealed that the prepared films are strongly oriented on (2 0 0) plane with rock-salt crystal structure. The various structural parameters such as grain size (D), lattice constant (a), micro strain (ε) and dislocation density (δ) were calculated. The surface morphology of the films was also analyzed. The optical absorption of the films starts with visible region and obtained energy gap of the films lies between 1.5 and 1.9 eV. The room temperature Photoluminescence spectrum shows the emission peak at visible region (380-405 nm) and the blue shift was observed with decreasing the film thickness. The electrical mobility, resistivity, carrier concentration and mean free path (L) of the free carriers of the films were studied for all the samples and compared.     

Size dependent optical characteristics of chemically deposited nanostructured ZnS thin films

ZnS thin films of different thicknesses were prepared by chemical bath deposition using thiourea and zinc acetate as S²⁻ and Zn²⁺ source. The effect of film thickness on the optical and structural properties was studied. The optical absorption studies in the wavelength range 250–750 nm show that band gap energy of ZnS increases from 3·68–4·10 eV as thickness varied from 332–76 nm. The structural estimation shows variation in grain size from 6·9–17·8 nm with thickness. The thermoemf measurement indicates that films prepared by this method are of n-type.     

Surface morphology and optical properties of magnetron - sputtered ultrathin Al films

Ultrathin Al films with different thicknesses were deposited on glass substrates by DC magnetron sputtering. The effects of film thickness on morphology and optical properties of the films were investigated in detail. When film thickness increases from 7.0 to 84.0 nm, the average grain size and surface roughness enlarges from 27.6 to 94.2 nm and from 0.25 to 1.87 nm, respectively. Below critical thickness of 28.0 nm, which is the thickness that Al films form continuous film, the optical properties vary significantly with thickness increasing and then tend to be stable. In the absorptance spectra, all films exhibit distinct broad peaks which can be attributed to the absorption due to the interband transition. The possible reasons for the shift in the peak position are due to the quantum size effects and internal stress in the ultrathin Al films.     

Grain growth of copper films prepared by chemical vapour deposition

Copper films having thickness 600 nm were prepared on TiN using chemical vapour deposition (CVD). The deposited films were annealed at various temperatures (350–550°C) in Ar and H₂(10%)-Ar ambients. The changes in the grain size of the films upon annealing were investigated. Annealing in an H₂(10%)-Ar ambient produced normal grain growth; annealing in an Ar ambient caused grain growth to stop at 550°C. The grain size followed a monomodal distribution and the mean size increased in proportion to the square root of the annealing time, indicating the curvature of the grain is the main driving force for grain growth. Upon annealing at 450°C for 30 min in an H₂(10%)-Ar ambient, the average grain size of the film increased from 122 nm to 219 nm, and the resistivity decreased from 2.35 μΩ cm to 2.12 μΩ cm at a film thickness of 600 nm. This revised version was published online in July 2006 with corrections to the Cover Date.     

The microstructure of aluminium thin films on amorphous SiO2

The microstructure of aluminium thin films deposited onto amorphous SiO₂ by tungsten filament evaporation was studied by transmission and scanning electron microscopy and grazing-incidence X-ray diffraction. The early stages of film growth were characterized by an island or connected-network structure and a random grain orientation. The thickness at which complete coverage occurred ranged from 15 nm at 295 K to 100 nm at 625 K, and above this thickness a 〈111〉 fibre texture became apparent.The grain size distribution of films 1 μm thick was log-normal and the average grain size ranged from 500 nm for deposition at 295 K to 4 μm for deposition at 675 K. “Growth hillocks” were observed on the surface of films deposited at 295 K but were absent when higher substrate temperatures were used. Annealing caused grain growth and the formation of “annealing hillocks” which were of different structure from the growth hillocks.Examination of a small number of electron-beam-deposited aluminium films showed these to have similar microstructures to the filament-evaporated films, whereas sputter-deposited films were characterized by a smaller grain size and random orientation.     

溅射Ar+能量对离子束溅射制备Ge薄膜结晶性的影响

采用离子束溅射技术在不同Ar 能量下溅射Ge单层膜.用Raman光谱和AFM图谱对薄膜进行表征,得到Ge薄膜结晶性和晶粒大小随Ar 能量变化的波动性关系.在0.6keV的Ar 能量下,得到晶粒较小的Ge晶化薄膜,0.8keV能量下,Ge薄膜为非晶结构,1.0keV能量下,得到晶粒较大的Ge晶化薄膜.通过对沉积原子数与沉积原子能量的分析,解释了这一波动性变化.     

Ar压强对硅基Al膜应力和微结构的影响

用直流磁控溅射法在室温Si基片上制备了溅射时间分别为5 min和10 min,氩气压强分别为0.7、3、6 Pa的6种Al膜,用光学相移法和X射线衍射法对Al膜的应力和微结构随着压强的变化进行了研究.应力分析表明:在同一溅射时间,随着氩气压强的减小,Al膜厚度增大,在相同选区范围内,Al膜的应力差变小,应力分布趋于均匀.结构分析表明:制备的Al膜呈多晶状态,晶体结构仍为面心立方,在相同溅射时间下,压强为0.7 Pa的Al膜结晶度最好.随着压强的减小,平均晶粒尺寸和晶格常数增大.