Study Of Orientations, Defects, Structures And Optical Properties Of ZnO Thin Films

ZnO is a wide direct-gap II -A/I group semiconductor material and the energy gap (Eg) is 3.37eV at room temperature. The exciton band energy of 60meV is higher than that of ZnS (40meV) and GaN (25meV) at room temperature, which assure ZnO realizes UV emission at higher temperature and higher emission efficiency at room temperature. It can be used to fabricate display devices, emitting diode, lasers. It has great uses in both civil and military field, so it attacts much attention from research group. In this thesis, we study the orientation, defects, structural and optical properties of ZnO thin films grown on sapphire by MOCVD and on Si subatrate by CVT.We study the structural and optical properties of ZnO thin films grown on sapphire by MOCVD. The results show that the ZnO thin films on sapphire are oriented along c-axis. The film thickness is namely the height of the columnar crystalline. The orientation relationships between ZnO films and substrate sapphire were characterized by the co rocking curve of ZnO (002) plane and the Φ scanning curve of ZnO (103) plane. ZnO thin films grown at substrate temperature of 600°C have good orientation and structure. The full wide at half maximum (FWHM) of the rocking curve for ZnO (002) plane grown at substrate temperature of 620°C reches to 6°. Φ scanning curves show that there exist two orientation relationships between...