生长温度对磁控溅射ZnO薄膜的结晶特性和光学性能的影响

采用反应射频磁控溅射方法，在Si (100) 基片上制备了具有高c轴择优取向的ZnO薄膜.利用 原子力显微镜、透射电子显微镜、X射线衍射分析、拉曼光谱等表征技术，研究了沉积温度 对ZnO薄膜的表面形貌、晶粒尺度、应力状态等结晶性能的影响；通过沉积温度对透射光谱 和光致荧光光谱的影响，探讨了ZnO薄膜的结晶特性与光学性能之间的关系.研究结果显示， 在室温至500℃的范围内，ZnO薄膜的晶粒尺寸随沉积温度的增加而增加，在沉积温度为500 ℃时达到最大；当沉积温度为750℃时，ZnO薄膜的晶粒尺度有所减小；在室温至750℃的范 围内，薄膜中ZnO晶粒与Si基体之间均存在着相对固定的外延关系；在沉积温度低于500℃时 ，制备的ZnO薄膜处于压应变状态，而750℃时沉积的薄膜表现为张应变状态.沉积温度的不 同导致ZnO薄膜的折射率、消光系数、光学禁带宽度以及光致荧光特性的变化，沉积温度对 紫外光致荧光特性起着决定性的作用.此外，探讨了影响薄膜近紫外光致荧光发射的可能因 素. 关键词： ZnO薄膜 表面形貌 微观结构 光学常数

Influences of growth temperature on the crystalline characteristics and optical properties for ZnO films deposited by reactive magnetron sputtering

Using reactive radio-frequency magnetron sputtering, ZnO films with strong c-axi s orientation have been deposited on Si (100) substrates at temperatures ranging from room temperature (RT) to 750℃. We have studied the influence of growth te mperature on the structural characteristics of the as-deposited films in morphol ogy, grain size, microstructure, and residual stress by using atomic force micro scopy, transmission electron microscopy, X-ray diffraction, and Raman spectrosco py. With the measurement of the transmission spectra and photoluminescence (PL) properties, the relationship between the crystallinity and optical properties of ZnO films have been discussed. It is found that the grain size increases with t emperature up to 500℃, and then decreases at 750℃. ZnO grains have an epitaxia l relationship with Si (100) substrate for the films deposited at the temperatur es ranging from RT to 750℃. The films deposited below 500℃ are in the states o f compressive strain while the film deposited at 750℃ is in tensile. The differ ence in growth temperature results in the variation of refractive index, extinct ion coefficient, optical energy gap, and PL properties of the films. It is concl uded that growth temperature dominates the PL behavior of ZnO films. We also dis cuss the physical mechanism affecting the PL behavior.