MgO(111)上ZnO薄膜的外延生长及其结构和光学特性

Structural and Optical Properties of ZnO Thin Films Grown on MgO(111) Substrates by Molecular Beam Epitaxy

摘要: 由于ZnO在光电器件的应用前景，其高质量薄膜的制备是研究热点之一。本文通过分子束外延生长法在MgO(111)单晶衬底上生长ZnO薄膜，表征了其结构和特性，探讨了不同生长条件对薄膜质量的影响。结果表明，先低温生长ZnO缓冲层，再高温生长ZnO薄膜，有望提高ZnO薄膜的质量。原位反射高能电子束衍射(RHEED)和异位的X射线衍射(XRD)分别测量出薄膜的面内结构和沿[0001]的单晶域高取向结构，并确定薄膜和衬底的外延关系为ZnO[01-10]//MgO[1-10]和ZnO[2-1-10]//MgO[11-2]。透射谱显示了ZnO的特征光学带隙。

Abstract: The growth of high quality ZnO films is highly desirable due to the promising applications of ZnO in optoelectronics. In this paper, ZnO films were grown on the MgO(111) substrates via the growth technique of molecular- beam epitaxy and their structural and optoelectronic properties were characterized. In particular, the influence of growth condition on the film qualify was investigated. The results show that, inducing a low temperature ZnO buffer layer before the high temperature growth of ZnO films will help to improve the film quality. In situ reflection high-energy electron diffraction (RHEED) and ex situ X-ray Diffraction (XRD) measurements indicate that the ZnO film and the MgO substrate follow the epitaxial relationship: ZnO[01-10]//MgO[1-10] and ZnO[2-1-10]//MgO[11-2]. Transmission Spectra show the characteristic optical bandgap of ZnO.