EPITAXIAL GROWTH OF NON-POLAR A-PLANE ZNO ON R-PLANE SAPPHIRE SUBSTRATES BY MOCVD AND RF-SPUTTERING

Epitaxial growth of non-polar thin films (a-plane ZnO) on sapphire (r-plane sapphire) were successfully implemented through metal organic chemical vapor deposition (MOCVD) and radio-frequency sputtering, respectively. For ZnO film deposited by sputtering, the growth temperature and the flow ratios of argon to oxygen were shown to significantly influence the crystalline quality and surface morphology of ZnO films. Flat surface ZnO epitaxial film can be grown by MOCVD. The epitaxial relationship between ZnO and sapphire substrate is and . The full width at half maximum (FWHM) of X-ray rocking curve for reflection peak depends on the orientation of X-ray beam toward sample surface. SEM and AFM observations show the surface morphologies of ZnO epilayers exhibit a stripe-like pattern along ZnO [0001] direction. The higher growth rate along ZnO [0001] and in-plane anisotropic lattice mismatch between a-plane ZnO and r-plane sapphire might result in the formation of such stripes.