Enhancement of the surface and structural properties of ZnO epitaxial films grown on Al2O3 substrates utilizing annealed ZnO buffer layers

Abstract

ZnO films were grown on Al 2 O 3 (1000) substrates without and with ZnO buffer layers by using radiofrequency magnetron sputtering. Atomic force microscopy images showed that the surface roughness of the ZnO films grown on ZnO buffer layers annealed in a vacuum was decreased, indicative of an improvement in the ZnO surfaces. X-ray diffraction patterns showed that the crystallinity of the ZnO thin films was enhanced by using the annealed ZnO buffer layer in comparison with the film grown on without a buffer layer. The improvement of the surface and structural properties of the ZnO films might be attributed to the formation of the Zn-face ZnO buffers due to annealing in a vacuum. These results indicate that the surface and structural properties of ZnO films grown on Al 2 O 3 substrates are improved by using ZnO buffer layers annealed in a vacuum.

High optical quality ZnO epilayers grown on sapphire substrates by reactive magnetron sputtering of zinc target

“…High-quality ZnO epilayers have usually been grown on crystalline substrates, such as sapphire by PLD [5][6][7], MBE [8][9][10] and MOCVD [11,12]. In recent years, there has been an increasing interest in the growth of ZnO epilayers by sputtering [13][14][15][16][17][18][19][20][21][22]. This is owing to the advantages of sputtering in terms of versatility, large-area deposition, low cost, high deposition rates and scalability.…”