CeO_2掺杂ZnO薄膜制备和紫外吸收性能

Effect of Doped-CeO_2 on the Structure and the Ultra-Violet Absorption Property of ZnO Thin Film

研究射频磁控溅射技术制备的CeO2掺杂ZnO薄膜的结构及紫外光吸收性能。结果显示,ZnO(002)晶面的晶面间距增大,由于晶格畸变的增加导致薄膜中的内应力也相应增加,随着CeO2掺入量的增加,引起ZnO晶格的进一步松弛,因此ZnO将呈混晶方式生长;由于ZnO的晶粒同时有多个生长方向,因而抑制了ZnO晶粒(002)取向生长度的速度,导致了晶粒尺寸的逐渐降低,薄膜的C轴择优取向性随CeO2含量的升高而降低。CeO2掺杂样品与纯ZnO薄膜的吸收谱的形状没有大的改变,吸收峰形基本一致,掺CeO2使薄膜的紫外吸收显著增强,吸收边明显向短波方向移动,吸收边的斜率有微小提高,吸收峰宽度略微增大,吸收强度增加。

ZnO thin film is a compound semiconductive material of hexagonal Wurtzite structure with a wide application in many areas such as transitive conductive window materials, ultraviolet detectors, LEDs and LDs luminance devices due to its unique electrical and optical properties, good chemical stability, high active energy and melting point, abundance, cheap and nontoxic source, and relatively low preparation temperature. Recent researches show that the properties of ZnO thin film are greatly changed while being doped with some elements. In our experiment, high quality ZnO thin films doped with Ce02 were prepared by RF magnetron sputtering technique. The influence of CeO2 on the structure and optic absorption property was studied by XRD apparatus and UV-visible spectrophotometer. The results show that the CeO2- doped films have a prominent effect on the developing ways of crystal grains and UV absorption property. The lattice relaxation and the content of second phase increase when more Ce is doped. ZnO crysal grains grow in mixing directions. The element Ce exists in many forms in the film. The film＇s UVA absorption is enhanced. The ultraviolet absorption peak becomes wider and the absorption intensity increases. The slope of the absorption margin is increased and the absorption edge obviously moves to short wave direction when more Ce is doped. In addition, the breadth of the absorption peak is increased and the absorption intensity improved. The visible absorption increases in some extent.