退火温度对ZnO薄膜结构和发光特性的影响

采用反应射频磁控溅射法在 Si(100)基片上制备了高c轴择优取向的ZnO薄膜，研究了退火温度对ZnO薄膜的晶粒尺度、应力状态、成分和发光光谱的影响，探讨了ZnO薄膜的紫外发光光谱和可见发光光谱与薄膜的微观状态之间的关系.研究结果显示,在600—1000℃退火温度范围内，退火对薄膜的织构取向的影响较小，但薄膜的应力状态和成分有比较明显的变化.室温下光致发光光谱分析发现，薄膜的近紫外光谱特征与薄膜的晶粒尺度和缺陷状态之间存在着明显的对应关系；而近紫外光谱随退火温度升高所呈现的整体峰位红移是各激子峰相对比例变关键词：ZnO薄膜退火光致发光射频反应磁控溅射可见光发射

Influence of annealing temperature on the microstructure and photoluminescence of ZnO films

ZnO thin films with strong c-axis prefered orientation have been successfully deposited on Si(100) substrate at 750℃ by using reactive radio frequency magnetron sputtering. The influence of annealing temperature ranging from 600 to 1000℃on the microstructure and photoluminescence (PL) properties of ZnO films was investigated by Ｘ-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence measurement at room temperature. The XRD and TEM results show that the grain size of ZnO film increases and the residual stress in the film is tensile and remains constant at about 1 GPa with the increase of annealing temperature below 900℃. After annealed at 1000℃, the grain size decreases and the residual stress in the film changes into compressive with the value about -2 GPa. The PL spectra of the ZnO films show two emission bands, namely that originating from ultraviolet (UV) exciton transition and the visible defect photoluminescence. The intensity of UV PL spectrum and the relative intensity of fferent exciton emission are dependent on the grain size and defects in the ZnO film. The red shift of UV PL spectrum results from the change of the relative intensity of different exciton emission with annealing temperature. The visible PL spectrum is sensitive to the change of annealing temperature. The relationship between PL spectra and microstructure and defects in the films is discussed.