透明致密ZnO薄膜的恒电流沉积及生长过程研究

Growth Process of Transparent and Compact ZnO Films Prepared by Galvanostatic Deposition

采用阴极恒电流沉积方法,以Zn(NO3)2水溶液为电沉积液,在经电化学预处理后的ITO导电玻璃上生长了具有c轴高度择优取向、均匀致密的透明ZnO薄膜．采用X射线衍射、扫描电镜和光学透过谱等技术,对不同沉积时间条件下薄膜的结晶特性、表面和断面结构、光学性质等进行了研究．结果表明,沉积时间对ZnO薄膜质量影响明显:在薄膜生长后期(120min),ZnO薄膜的结晶性和表面平整度明显降低,晶粒尺寸增大,可见光透过率下降,表明高质量ZnO薄膜的电化学沉积有一最佳生长时间;此外,薄膜厚度随时间呈线性变化,表明可通过生长时间实现对ZnO薄膜厚度的精确控制．

Transparent and compact ZnO thin films with high c-axis preferred orientation were galvanostatically deposited in Zn（NO3）2 solutions on the ITO substrate after an electrochemical pretreatment process. The crystallinity, microstructure of surface and cross section, and optical properties of obtained films were characterized by X-ray diffraction, scanning electron microscope and optical transmittance spec- tra. Results show that the deposition time has significant influences on the quality of ZnO films. At the later stage of film deposition （120min）, ZnO film exhibits obvious decrease in the crystalline degree, surface smoothness, and transmittance, with the increase of crystailite sizes, which indicates that the deposition time must be optimized to obtain the electrodeposited ZnO film with high quality. In addition, the film thickness linearly changes with deposition time, illustrating the possibility to control the film thickness by deposition time.