ZnS薄膜的水浴法制备及其光学性能

以酒石酸和柠檬酸钠为络合剂,采用水浴法(CBD)制备ZnS薄膜.利用X射线衍射(XRD)、X射线能谱仪(EDAX)、扫描电镜(SEM)、紫外-可见分光光度计(UV-vis)研究ZnS薄膜的结构、成分、形貌及光学性能.利用透射光谱计算了ZnS薄膜的光学禁带宽度.结果表明:ZnS薄膜呈立方相晶体结构,水浴沉积时间为3h的ZnS薄膜原子比Zn∶S为1∶0.85,薄膜表面均一致密,在可见光区有着好的透射性能,在300～800 nm的光谱范围内平均透射率达到80.8%,光学禁带宽度为3.78eV,适合作为太阳能电池过渡层.     

络合剂对化学水浴沉积 ZnS薄膜的影响

采用不同络合剂化学水浴沉积ZnS薄膜,应用台阶仪、SEM、XRD、波谱仪等手段测定了ZnS薄膜的厚度、表面、物相结构及透过率等.结果表明,氨水体系沉积薄膜速度明显慢于另外两种体系,沉积的ZnS薄膜都为立方结构.柠檬酸钠体系沉积的ZnS 薄膜结晶和透过率最佳,但薄膜表面缺陷较多;氨水-联氨体系沉积的ZnS薄膜表面质量最佳,结晶和透过率也较好;氨水体系沉积的ZnS薄膜质量较差.用3种体系沉积的ZnS薄膜用于制备铜铟镓硒Cu(In,Ga)Se2太阳电池,氨水和氨水-联氨体系沉积的ZnS薄膜制备的电池转换效率明显高于柠檬酸钠体系沉积的ZnS制备的太阳电池.     

化学水浴法制备ZnS薄膜及其光学性能

以酒石酸与柠檬酸钠为络合剂,采用化学水浴法(CBD)沉积ZnS薄膜.利用X射线衍射仪(XRD)、X射线能谱仪(EDAX)、扫描电镜(SEM)、紫外-可见分光光度计(UV-Vis)研究ZnS薄膜的结构、组成、形貌及光学性能,利用透射光谱计算ZnS薄膜的光学禁带宽度(Eg).结果表明:ZnS薄膜呈立方相晶体结构,经过300℃熟处理1h的ZnS薄膜原子比为Zn:S=1:0.85,表面均一致密,在可见光区的平均透射率达到80%,光学禁带宽度为3.74ev,适合作为太阳能电池过渡层.     

离子束增强反应磁控溅射低温快速沉积AlN膜

本文采用氮离子束增强反应磁控溅射,在低温下沉积了 AlN 薄膜.用 X 射线衍射和 X 射线光电子谱对薄膜的晶体结构和电子结构进行了分析,结果表明,随着离子源中氮离子束流的增加,薄膜组成由面心立方的 Al 转变为密排立方的 AlN.氮离子在薄膜制备中的引入,有效地降低了沉积温度,提高沉积速率,并实现了薄膜 N/Al 化学计量比的控制.对 AlN 薄膜的紫外-可见光透射谱和红外吸收谱也进行了测定.     

PLD法在c面蓝宝石衬底上制备纤锌矿ZnS外延薄膜

采用脉冲激光沉积方法以ZnS为靶材c面蓝宝石为衬底制备了一系列的ZnS薄膜,并采用四圆单晶衍射仪研究了薄膜的晶体结构及其与衬底的取向关系。首先研究了沉积温度对ZnS薄膜质量的影响,结果表明,所有制备的ZnS薄膜均为六方纤锌矿结构;在衬底温度为750℃时所制备的薄膜具有较好的晶体质量,并表现出与蓝宝石衬底明确的外延关系[ZnS(001)∥Al_2O_3(001)且ZnS(110)∥Al_2O_3(110)]。进一步研究了在750℃下加入不同厚度的ZnO缓冲层对于ZnS薄膜晶体质量的影响,结果表明在沉积ZnS薄膜前先沉积一层ZnO薄膜缓冲层可以进一步有效提高ZnS薄膜的晶体质量和面外取向性,其中在沉积时间为2min的ZnO缓冲层上制备的ZnS外延薄膜晶体质量最好,其(002)面摇摆曲线半高宽为1.35°。本文结论对于研究ZnS薄膜制备光电器件具有重要的意义。     

热丝CVD制备微晶硅薄膜的研究

采用热丝化学气相沉积技术制备微晶硅薄膜,利用X射线衍射谱、Raman散射谱、透射光谱和扫描电子显微镜等检测手段,系统地研究沉积过程中沉积气压对微晶硅薄膜晶粒尺寸、晶态比和光学带隙的影响,运用Tacu法则对薄膜的透射率和厚度进行计算分析,得到薄膜光学带隙与沉积气压之间的关系,结果表明薄膜的光学带隙随着沉积气压的升高而单调下降。     

衬底温度对ZnS薄膜微结构和应力的影响

采用射频磁控溅射法分别在不同温度衬底上制备了厚度为320nm的ZnS薄膜,用XRD和光学相移技术研究了不同衬底温度下薄膜的微结构和应力.结果表明:不同温度衬底上沉积的ZnS薄膜均呈多晶状态,衬底温度由50℃上升到400℃的过程中,其择优取向发生了变化,晶粒有明显的生长方向;ZnS薄膜应力随着衬底温度升高逐渐减小,衬底温度在250～350℃之间的ZnS薄膜应力较小且在选区内分布比较均匀.     

非晶态和纳米晶碳化硅薄膜的制备及力学性能

以SiC超细粉为原料、利用热等离子体PVD(TPPVD)技术快速制备出了优质非晶态和纳米晶SiC薄膜.用扫描电子显微镜、高分辨透射电子显微镜、X射线衍射和X射线光电子谱、红外分光谱对薄膜的微结构进行了观察和分析.用纳牛力学探针测量了薄膜的力学性能.研究结果表明,只有当基板温度低于600℃、粉末供给速度不超过20mg/min时可沉积非晶态SiC薄膜,最大沉积速度达到25nm/s;当基板温度在600℃～1000℃时沉积的β-SiC薄膜是晶粒大小为3 nm～5 nm的纳米晶薄膜,最大沉积速度达到230 nm/s.非晶态和纳米晶SiC薄膜的硬度分别达到33.8 GPa和38.6 GPa.     

原位退火处理对ZnS/Si薄膜结晶性能的影响

采用脉冲激光沉积法在Si衬底上生长出厚度为400nm的一系列ZnS薄膜,进行原位退火处理,获得单晶结构的闪锌矿型ZnS薄膜。首次报道了采用原位退火处理后获得单晶ZnS薄膜为立方结构的闪锌矿且薄膜沿(111)晶面择优生长,同时研究了其结晶质量与退火工艺之间的关系。结果显示随着退火温度的升高,薄膜的平均晶粒尺寸由200℃的13.357nm增长到400℃的27.232nm,另外薄膜的平均粗糙度由2.05nm下降达到1.14nm。采用脉冲激光沉积法制备的ZnS薄膜在400℃退火后表现出极好的单晶择优取向生长以及良好的表面平整度,为研究单晶ZnS薄膜提供一种实验解决思路。     

SiC/C薄膜的制备及其力学性能

以SiC 超细粉为原料、采用热等离子体物理气相沉积( TPPVD) 技术快速制备出了高质量SiC/ C 薄膜, 最大沉积速度达到225 nm/ s, 高于常规物理气相沉积( PVD) 和化学气相沉积(CVD) 法两个数量级。用扫描电子显微镜、高分辨透射电子显微镜和X 射线光电子谱对薄膜的形貌和微结构进行了观察和分析, 并用纳牛力学探针测定了薄膜的力学性能。研究结果表明, 向等离子体中导入CH₄, SiC/ C 薄膜沉积速度增大, 薄膜中C 含量增加, 薄膜断面呈现柱状结构。薄膜硬度和弹性模量随薄膜中C 含量增加而降低, 在接触深度为40 nm 时由纳牛力学探针测得沉积薄膜的最大硬度达到38 GPa。     

温度对化学水浴法制备ZnS薄膜的影响

采用化学水浴法在玻璃上制备了太阳能电池中的ZnS缓冲层。采用SEM、EDS、XRD和nkd-分光光度计等手段研究了水浴温度对ZnS薄膜的表面形貌、结构和光学性能的影响。结果表明,升高温度不能明显改变薄膜的结晶性、形貌和沉积生长方式,能否成膜与温度的关系也不大,但成膜速率对温度的依赖性较大。随温度的升高,薄膜的透过率先减小后增大,反射率则先增大后减小。对同一试样而言,透过率和反射率对应较好。当温度为70℃时,可制得禁带宽度为3.83eV、符合化学计量比、平整的非晶ZnS薄膜。     

ZnS薄膜沉积过程的基材效应

采用热蒸发及离子束辅助沉积技术制备了单层ZnS薄膜,研究了Si、Ge、K9及石英玻璃基材对薄膜沉积速率及光学特性的影响。采用椭偏法拟合了薄膜的厚度和折射率,分析了不同基材上沉积薄膜的色散特性。研究结果表明,薄膜的生长存在明显的基材效应,无论室温沉积、基温200℃,还是采用离子束辅助沉积,石英基材上均具有最高的沉积速率。室温沉积时,4种基材上薄膜的沉积速率差为3.3 nm/min,加热进一步扩大了这种差异(5.2 nm/min),而离子束辅助则在一定程度上缩小了这种差异(1.86 nm/min)。在室温下,石英基材上沉积的ZnS薄膜具有最低的折射率,其他几种基材上折射率差异不大。加热会使Si、Ge及K9玻璃上的折射率差异变大,与石英玻璃上薄膜折射率差异减小,离子源的使用则进一步缩小了这种差异。透射率光谱测试证实了这一结果。     

Preparation and characterization of ZnS thin films by the chemical bath deposition method

ZnS thin films prepared on quartz substrates by the chemical bath deposition (CBD) method with three type temperature profile processes have been investigated by X-ray diffraction, scanning electron microscope, energy dispersive X-ray analysis and light transmission. One is a 1-step growth process, and the other is 2-steps growth and self-catalyst growth processes. The surface morphology of CBD-ZnS thin films prepared by the CBD method with the self-catalyst growth process is flat and smooth compared with that prepared by the 1-step and 2-steps growth processes. The self-catalyst growth process in order to prepare the particles of ZnS as initial nucleus layer was useful for improvement in crystallinity of ZnS thin films prepared by CBD. ZnS thin films prepared by CBD method with self-catalyst growth process can be expected for improvement in the conversion efficiency of Cu(InGa)Se₂-based thin film solar cells by using it for the buffer layer.     

The influence of deposition parameters on the optical properties and growth of ZnS films

A vacuum automatic ellipsometer was used to observe and reveal the effect of the rate of deposition on the structural irregularities of ZnS films during growth.The high accuracy and sensitivity of this instrument were exploited for measuring the refractive index of ZnS films prepared at various rates of deposition and substrate temperatures.     

Optical properties of nanocrystalline ZnS:Mn thin films prepared by chemical bath deposition method

Nanocrystalline ZnS:Mn thin films were fabricated by a chemical bath deposition route on glass, silicon, and quartz substrates using a weak acidic bath, in which citrate ions acts as a nontoxic complexing agent for zinc ions and thioacetamide acts as a source of sulfide ions at 60 °C. The composition of films were characterized by energy-dispersive X-ray spectrometer, inductively coupled plasma atomic emission spectroscopy, Rutherford backscattering, and attenuated total reflection-Fourier transform infrared spectroscopy. X-ray diffraction pattern and transmission electron microscopy image confirm that the films have nanocrystalline nature. The band gap energy of ZnS:Mn films is blue-shifted by about 0.3 eV with respect to the bulk value (3.67 eV), probably due to the quantum size effect as expected from the nanocrystalline nature of the ZnS:Mn thin films. The dispersion and optical constants of the films were determined. These parameters changed with the deposition time.     

三元体系化学水浴法制备ZnS薄膜结晶性能的研究

太阳薄膜电池ZnS缓冲层一般以氨水为主络合剂、水合肼为辅助络合剂二元络合体系化学水浴法制备。实验发现以氨水为主络合剂、水合肼和柠檬酸为辅助络合荆三元体系制备的ZnS薄膜质量明显要比氨水、水合肼二元体系的ZnS薄膜好。薄膜表面更加光亮、平整，光透过率能得到明显提高。从实验现象和测试结果来看，随柠檬酸浓度增加，在反应溶液中无定形态白色沉淀明显减少，ZnS薄膜结晶性能也得到明显提高，ZnS薄膜光透过率升高。柠檬酸浓度为0．15mol／L时，薄膜光透过率达到85％左右，完全满足太阳能电池的要求；继续增加柠檬酸的量，薄膜光透过率趋于一致，光透过率略有回落。     

Substrate temperature influence on ZnS thin films prepared by ultrasonic spray

ZnS thin films were deposited by ultrasonic spray technique. The starting solution is a mixture of 0.1 M zinc chloride as source of Zn and 0.05 M thiourea as source of S. The glass substrate temperature was varied in the range of 250 °C-400 °C to investigate the influence of substrate temperature on the structure, chemical composition and optical properties of ZnS films. The DRX analyses indicated that ZnS films have nanocrystalline hexagonal structure with (002) preferential orientation and grain size varied from 20 to 50 nm, increasing with substrate temperature. The optical films characterization was carried out by the UV-visible transmission. The optical gap and films disorder were deduced from the absorption spectra and the refractive indices of the films were determined by ellipsometric measurements. It is shown that the obtained films are generally composed of ZnO and ZnS phases with varied proportion, while at deposition temperature of 400 °C, they are near stoichiometric ZnS.     

Control of ZnO thin film surface by ZnS passivation to enhance photoluminescence

To enhance the optical property of zinc oxide (ZnO) thin film, zinc sulfide (ZnS) thin films were formed on the interfaces of ZnO thin film as a passivation and a substrate layer. ZnO and ZnS thin films were deposited by atomic layer deposition (ALD) using diethyl zinc, H₂O, and H₂S as precursors. Investigations by X-ray diffraction and transmission electron microscopy showed that ZnS/ZnO/ZnS multi-layer thin films with clear boundaries were achieved by ALD and that each film layer had its own polycrystalline phase. The intensity of the photoluminescence of the ZnO thin film was enhanced as the thickness of the ZnO thin film increased and as ZnS passivation was applied onto the ZnO thin film interfaces.     

Deposition of ZnS thin films by photochemical deposition technique

ZnS thin films have been deposited on a glass substrate by photochemical deposition (PCD) technique from an aqueous solution. The effect of pH and stirring speed of the solution on deposition has been studied. The optical transmission spectra of the solutions have been recorded before and after deposition and also for the deposited film. The as-deposited and annealed films were characterized by X-ray diffraction (XRD) and it is observed that the crystallinity of the deposited films is improved by annealing at various temperature from 100 to 500 °C. The surface coverage of the film has been studied using optical microscope.     

High refractive index films of ZnS/PVP nanocomposite by in situ thermolysis

A simple and rapid process for deposition of high refractive index films of ZnS/PVP nanocomposite (NC) is described. Precursor films are dip-coated on glass/quartz substrates from methanolic solution of polyvinylpyrrolidone (PVP) containing Zn⁺²–thiourea (TU) complex. ZnS/PVP nanocomposite films are produced by heating the solid precursor at 200°C for 10 min in air. Heat treatment converts the Zn⁺²–TU complex to ZnS by thermolysis in situ PVP. The transmission spectra of the films (typically 700 nm thickness) in the wavelength range of 200–1000 nm showed an absorption edge near 300 nm due to ZnS nanoparticles and high transmission of 97% beyond 400 nm. ZnS nanoparticles are uniformly dispersed in PVP matrix having sizes of about 3–4 nm. For ZnS loading of 45% by weight, the refractive index of ZnS/PVP is 1.65 which is in between that of PVP (1.48) and ZnS (2.36). Fourier Transform Infrared (FTIR) spectroscopy of the composite showed that there is a strong interaction between ZnS nanocrystals and PVP. The root mean square (RMS) roughness of the films is about 3 nm as determined by atomic force microscope (AFM).