在不同的衬底温度下,采用磁控溅射方法在蓝宝石(0001)衬底上制备了外延生长的ZnO薄膜。采用原子力显微镜(AFM)、X射线衍射仪(XRD)、可见-紫外分光光度计系统研究了衬底温度对ZnO薄膜微观结构和光学特性的影响。AFM结果表明在不同衬底温度制备的ZnO薄膜具有较为均匀的ZnO晶粒,且晶粒的尺寸随衬底温度的增加逐渐增大。XRD结果显示不同温度生长的ZnO薄膜均为外延生长,400℃生长的薄膜具有最好的结晶质量;光学透射谱显示在370nm附近均出现一个较陡的吸收边,表明制备的ZnO薄膜具有较高的质量,其光学能带隙随着衬底温度的增加而减小。
Epitaxial ZnO thin film has been fabricated on sapphire substrate(000l) using RF magnetron sputtering at different substrate temperature. The influence of substrate temperature ranging from room temperature to 700℃on the microstructural and optical properties of ZnO films is investigated by atomic force microscopy (AFM), X-ray diffraction(XRD), ultraviolet-visible absorption spectroscopy at room temperature. The AFM results show that the uniform grain sized ZnO films are deposited at different substrate temperature and the grain size of ZnO film increases with the increase of substrate temperature. The XRD measurements indicate that the ZnO films grown on sapphire are epitaxial with wurtzite structure and the film fabricated at 400℃ has the best crystalline quality. Optical transmission spectra of the ZnO samples demonstrates that the same abrupt absorption edge of the film appears at about 370nm, implying high quality of the ZnO film prepared at different substrate temperature. The optical band gap of ZnO films decreases with the increase of growth temperature.