Effects of Buffer-layer Thickness and Active-layer Growth Temperature on ZnO Nanocrystalline Thin Films Grown by Molecular Beam Epitaxy

ZnO thin films were deposited on a Si (100) substrate by plasma-assisted molecular beam epitaxy (PA-MBE). Growth of ZnO thin films on a Si substrate is limited due to the large difference between the lattice constants of ZnO and Si. In this research, we studied the effects of the buffer-layer thickness and active-layer growth temperature on the structural and optical properties of ZnO thin films. Scanning electron microscopy, X-ray diffraction, and photoluminescence were carried out to investigate the structural and optical properties of the ZnO thin films. The structural and optical properties of the ZnO thin films were improved when the buffer layers were grown for 20 min and the active layers were grown at 800 degrees C.