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.     

CdS纳米晶薄膜的制备及光电性能研究

利用化学浴沉积法,以N(CH2CH2OH)3为络合剂,Cd(CH3COO)2·2H2O和(NH2)2CS为前驱体溶液制备了CdS纳米晶薄膜,利用FESEM、XRD考察了前驱体浓度、络合剂浓度、前驱体溶液的pH值、反应温度等因素对CdS纳米晶薄膜的表面形貌、晶粒大小及晶体结构的影响,在最佳工艺条件下可以制得表面平整,结构致密的CdS纳米晶薄膜。UV-Vis光谱表明CdS在短波长区域有较强的吸收,符合作为窗口材料和过渡层的要求;光电性能测试表明CdS具有较好的光电响应,呈特征n型半导体特性。     

CdS量子点敏化纳米TiO_2异质薄膜的制备和表征

以异丙醇钛(C12H28O4Ti)为主要原料合成氧化钛(TiO2)前驱体溶胶,并结合230℃水热处理得到TiO2溶胶,利用电流体动力学(EHD)技术在掺氟氧化锡导电(FTO)玻璃基片上镀膜,450℃高温煅烧制备具有多级结构锐钛矿TiO2纳米薄膜。以硝酸镉(Cd(NO3)2)及硫化钠(Na2S)分别为镉源和硫源,采用化学浴沉积技术在TiO2薄膜上沉积制备了量子点敏化的异质薄膜。采用X射线衍射(XRD)、电子扫描电镜(SEM)、电子透射电镜(TEM)以及紫外-可见吸收光谱(UV-Vis absorbance spectra)对薄膜结构和性能进行表征。结果表明,纳米TiO2薄膜具有亚微米球簇堆积结构,球簇之间形成尺寸连续分布的微纳通道,便于溶液的浸润和离子的表面吸附。敏化制备异质薄膜中硫化镉以量子点状态存在,晶粒尺寸为3～5nm范围内。UV-Vis吸收光谱证实量子点的量子限域效应,吸收发生蓝移现象。     

无电流电场沉积CdS纳米薄膜

针对普通电沉积制备纳米薄膜工艺中的电极析气、电解、电镀等有害电极反应对沉积过程和沉积膜造成不良影响的问题,提出了一种待沉积薄膜的基材及其上的沉积膜不与沉积电路组成闭合电流回路的电场沉积装置及电场沉积制备纳米薄膜的新方法.在自制的电场沉积装置上制备了CdS薄膜并用AFM表征了薄膜微观结构.获得了粒径约30nm的CdS微粒致密平整薄膜.研究结果表明,新方法具有薄膜质量好、无需使用贵金属电极、沉积速度快等优点.     

Dy掺杂的CdS薄膜的制备及性能分析

采用化学水浴法在玻璃衬底上制备纯的和稀土Dy掺杂的CdS薄膜,并在N2气氛中,对以上制备的薄膜进行T=350℃、t=40min的热处理.实验结果表明,水浴温度在70℃～80℃间制备的CdS薄膜,表面致密、光滑,膜的质量最好,且为沿[111]晶向择优生长的立方闪锌矿结构.掺Dy虽未改变CdS薄膜的晶体结构,但改善了薄膜的表面形貌,使得薄膜的致密性增强、颗粒大小匀称,同时Dy的掺入增大了CdS薄膜在可见光范围内的透光率.     

退火时间对PbS薄膜结构和光学特性的影响

利用化学浴沉积法在玻璃衬底上50℃沉积3h制备硫化铅(PbS)纳米晶薄膜。将得到的PbS薄膜在300℃氮气中进行不同时间(0~120min)的退火。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、原子力显微镜(AFM)和紫外-可见-近红外分光光度计对PbS薄膜的结构和光学特性进行研究。PbS薄膜在玻璃基底上粘附力较强,结晶度良好,呈面心立方结构且沿(111)方向择优生长。不同的退火时间导致PbS薄膜的结构、形貌、光学特性均产生明显差异。退火30min的PbS薄膜的结晶度最好,其带隙变化范围为0.90~1.70eV。     

磁控溅射法制备CdS多晶薄膜工艺研究

采用磁控法制备了CdS薄膜,研究工艺参数对样品沉积质量、沉积速率及晶体结构的影响。实验发现,在不同衬底上制备CdS薄膜时需要采取不同的后续工艺措施以获得较好的沉积质量。同时,制备样品的沉积速率随衬底类型、衬底温度、溅射功率及溅射气压的变化而变化。讨论并给出了工艺参数对上述实验结果的影响机制。X射线衍射谱显示,制备样品是六方和立方两种晶型的混合,沿(002)和(111)晶面择优取向生长。随溅射功率的增大和衬底温度的升高,两种晶型互相竞争生长并分别略微占优势。当溅射功率增大到200 W,衬底温度升高到200℃时,占优势晶型消失,薄膜择优取向特性变得更好。此外,随着溅射气压的增大,样品结晶质量下降,在0.5 Pa时呈现明显非晶化现象。     

化学沉积参数对CdS薄膜前驱物利用率的影响

采用化学水浴法,在醋酸镉、硫脲、氨水、醋酸铵的体系中制备CdS薄膜,设计L2556正交实验,研究了各沉积参数对前驱物利用率的影响.结果表明,随前驱物醋酸镉、硫脲各自浓度的增加,其自身的利用率下降,但另一方的利用率上升.前驱物的利用率随络合剂醋酸铵浓度的增加先增大后减小,随氨水浓度的增加先减小后增大;其利用率随反应条件温...     

掺In纳米ZnO、CdS薄膜结构、光学特性分析

采用真空气相沉积法在玻璃衬底上制备纳米级ZnO和CdS薄膜.研究掺In和热处理对ZnO、CdS薄膜结构、光学特性的影响.实验给出,适当掺杂能够明显改善纳米ZnO、CdS薄膜的物相结构,ZnO薄膜的晶粒尺寸随掺杂含量的增加而减小,CdS薄膜晶粒尺寸随掺杂含量的增加而变大,但薄膜的光透射性有所降低.在短波范围内,ZnO薄膜的光透率好于CdS薄膜;在500 nm～1000 nm范围内,CdS薄膜的光透率好.掺In后ZnO薄膜的光学带宽从3.2eV减小至2.85 eV;掺In后CdS薄膜光学带宽从2.42 eV减小至2.35eV.     

Structural and optical properties of CdS thin films grown by chemical bath deposition

Cubic cadmium sulphide (CdS) thin films with (111) preferential orientation were prepared by chemical bath deposition (CBD) technique, using the reaction between NH₄OH, CdSO₄ and CS(NH₂)₂. The films properties have been investigated as a function of bath temperature and deposition time. Structural properties of the obtained films were studied by X-ray diffraction analysis. The structural parameters such as crystallite size have been evaluated. The transmission spectra, recorded in the UV visible range reveal a relatively high transmission coefficient (70%) in the obtained films. The transmittance data analysis indicates that the optical band gap is closely related to the deposition conditions, a direct band gap ranging from 2.0 eV to 2.34 eV was deduced. The electrical characterization shows that CdS films' dark conductivities can be controlled either by the deposition time or the bath temperature.     

快速升温法制备CdS纳米带的生长机理研究

在无任何催化剂的条件下, 采用快速升温法在单晶硅衬底上制备了高质量的、形貌均匀的CdS纳米带. X射线衍射(XRD)、透射电镜(TEM)和场发射扫描电镜(FESEM)分析显示, 纳米带属六方单晶结构, 生长方向为[001]. 讨论了纳米带形成的机理, 认为CdS纳米带状六方结构的形成, 主要是由于生长速度的各向异性及在沉积区具有较低的过饱和度和较高的沉积温度等因素导致.     

Influence of substrates on the structural and optical properties of chemically deposited CdS films

Cadmium sulfide (CdS) films were chemically deposited on glass, polycarbonate (PC), polyethylene terephthalate (PET), and Si wafer. Effects of substrate types on the structural and optical properties of the films were investigated. There is a preferential orientation of the crystallites in the film grown on the glass along the c-axis (perpendicular to the plane of the substrate) producing a strong hexagonal (0 0 2) or cubic (1 1 1) peak, regardless of the presence of ITO coating. However, such preferential orientation decreases or disappears when the deposition was made onto PC or PET substrates. The crystallinity of CdS films on glass and Si is better than that of the other ones. The average transmittance of the films on PC and PET is about 50% and 55%, respectively, and increases up to 70% for glass substrate. The improvement of the transmittance was obtained from ITO-coated substrates.     

Chemical bath deposition of CdS thin films and their partial conversion to CdO on annealing

CdS thin films prepared by chemical bath deposition technique are characterized using X-ray diffraction, optical absorption spectrometry and scanning electron microscopy. The results of the annealing studies on the films in flowing argon and air atmospheres are also presented in this paper. The resistivity has drastically reduced on annealing in flowing air which is attributed to the partial conversion of CdS to CdO phase.     

Structural study of the initial growth of nanocrystalline CdS thin films in a chemical bath

Nanocrystalline cadmium sulfide CdS thin films with relevance for optical applications were synthesized from aqueous solutions by chemical bath deposition. Grazing incidence X-ray diffraction shows that the films formed on glass or silicon substrates are made up of nanocrystalline particles. About 80% of the particles have a diameter of 5 ± 1 nm. The nanoparticles have either sphalerite or wurtzite structure. The presence of the sphalerite phase is a signature of a highly non-equilibrium state of the nanocrystalline film. Kinetic studies show that the size of the nanocrystals and the relative fraction of the two phases do not depend on the deposition time once it exceeds a duration of 30 min. For longer times, the particle characteristics remain constant while the thickness of the film grows. Thermodynamical analysis of ionic equilibria allows to choose the reaction bath composition for the formation of cadmium hydroxide Cd(OH)₂. The experiments provide strong evidence that the beginning of the deposition of CdS is accompanied by a formation of cadmium hydroxide Cd(OH)₂.     

复合结构纳米晶CdS：Cu/CdS的制备及光学特性

在非配位溶剂中合成了高质量的CdS纳米晶核,并利用Cu2+离子对其进行掺杂,制备了CdS:Cu纳米晶.通过进一步采用连续离子层吸附反应的方法对CdS:Cu纳米晶进行表面修饰,得到CdS:Cu/CdS复合结构纳米晶.利用X射线衍射(XRD),透射电镜(TEM),紫外可见吸收光谱(UV-Vis)和荧光光谱(PL)对其结构、形貌以及光学性质进行了表征和分析,结果表明:所制备的复合结构CdS:Cu/CdS纳米晶为立方闪锌矿结构;与CdS纳米晶核相比,掺杂Cu2+可以使其表面态发光发生红移;在CdS:Cu纳米晶中,通过改变掺杂Cu2+的浓度,可以实现表面态发光在570和620nm之间的连续调节.与未经包覆的CdS:Cu纳米晶相比,包覆层CdS增强了纳米晶CdS:Cu的稳定性.     

Photoconductive and ellipsometric studies of spray pyrolysed CdS thin films

The influence of annealing temperature on photoconductivity of spray pyrolysed CdS films has been investigated. The annealing of films at 373K resulted in maximum photoconductivity. The photoconductivity at all wavelengths was found to decrease with increase of annealing temperature and became a minimum at 473K. For films annealed at or above 523K, the photoconductivity for wavelengths ⩾560 nm decreased considerably. The results are discussed with the help of ellipsometric data, visible and IR spectra of these samples. Also the variation in photoconductivity of these samples were studied during heating to analyse the effect of trapping.     

Brush electrodeposited CdS films on low temperature substrates

Cadmium sulphide films were deposited by the brush plating technique on titanium and conducting glass substrates using a current density of 80 mA cm^− 2. X-ray diffraction studies indicated the polycrystalline nature of the films with hexagonal structure. As the deposition temperature decreased, the peaks were broad indicating the formation of nanocrystallites. Optical absorption measurements yielded band gap values in the range of 2.39-3.10 eV as the deposition temperature decreases. XPS studies confirmed the formation of CdS. Atomic force microscope studies indicated the roughness of the films decreases with the decrease of deposition temperature. The as deposited films were photoactive.     

单分散球形硫化镉膜的电化学沉积

提出一种在ITO玻璃上电化学沉积制备单分散近球形硫化镉粒子的新方法.在S-CdCl2-DMSO电沉积体系中加入少量的水制备出单分散膜层,调节沉积电流、电沉积时间或Cd2 浓度可以改变膜层的粒子分布密度.结果表明,在电沉积的整个ITO玻璃表面上均分布有硫化镉沉积,且不同厚度膜层上的沉积其S与Cd的原子比不同.在电沉积硫化镉膜层上蒸镀铜酞菁制备出p-n异质结,其Ⅰ-Ⅴ特性表明,单分散近球形硫化镉膜层载流子的传输由带导电控制机制向跳跃导电控制机制转变.