退火温度对CdSe纳米薄膜的形成及光电性能影响

在室温下,采用循环伏安法在ITO上沉积CdSe纳米薄膜。利用X射线衍射仪(XRD)、场发射扫描电镜(FESEM)、原子力显微镜(AFM)、X射线光电子能谱分析(XPS)、紫外-可见(UV-VIS)分光光度计以及电化学工作站对不同温度退火后的CdSe纳米薄膜的晶体结构、形貌、光学性能、光电化学性能进行表征和测试。结果表明,退火温度对CdSe纳米薄膜的形貌和性能起到关键性作用。薄膜表面平整、厚度均匀,且由呈纳米颗粒状的立方相CdSe构成;经退火后,CdSe纳米颗粒出现不同程度的长大现象,Se含量随退火温度的升高而减少。紫外-可见吸收光谱表明随着退火温度的升高,CdSe纳米薄膜对可见光的吸收发生红移,表明禁带宽度逐渐减小,表现出量子尺寸效应。通过光电流测试表明随着退火温度的升高,CdSe薄膜的光电响应效应显著提高。

Influence of Annealing Temperature on CdSe Thin Films Forming and Photoelectric Characteristics

CdSe nano thin films were electrodeposited on ITO glass by using cyclic voltammetry method.The crystal structure, morphology, optical properties and photoelectric properties of CdSe nano thin films prepared with different temperature are investigated by X-ray diffraction(XRD), field emission scanning eletron microscopy(FESEM), atomic force microscope(AFM), X-ray photoelectron spectroscopy(XPS), UV-Vis spectra and electrochemical workstation.The results show that annealing temperature plays a critical role in morphology and properties of CdSe nano thin films. The sample, smooth surface and uniform thickness, consist of numorous nanoparticles with zinc blende phase, and the size of CdSe nanoparticles grew up as increasing the annealing temperature.The content of Selenium decreased with the increase of annealing temperature.Thus, the absorption peak of the samples have red shift and the band gap energy gradually decrease, which is due to quantum size effect.In addition, photocurrent test of the samples show obviously photoelectric response under visible light illumination, and the photocurrent density of the samples increased with increase of annealing temperature.