Plasma-assisted molecular beam epitaxy of polar and nonpolar ZnO: Growth and characterization

In this talk, plasma-assisted molecular beam epitaxy of polar and nonpolar ZnO epitaxial growth is presented. Two-dimensional layer-by-layer growth of ZnO films, with very high crystal qualities, on c-sapphire substrates was achieved by employing the novel buffer. Polarity of the (0001) ZnO thin films was controlled based on interface engineering and we could selectively grow Zn-polar and O-polar ZnO thin films on c-plane Al2O3 as well as on Ga-polar GaN templates by several different methods. Polarity inverted heterostructure, i.e., growth of O-polar ZnO film on Zn-polar ZnO by inserting an intermediate layer was tried and succeeded. For the growth of nonpolar ZnO films free of electric field effects along the growth direction, (11-20) ZnO films were epitaxially grown on r-plane Al2O3, Basic properties of the nonpolar ZnO films are investigated and those are top level in the ZnO fields and are comparable to nonpolar GaN grown by MOCVD. Details of the results will be discussed.
Soon-Ku Hong is an associate professor of Materials Science and Engineering at the Chungnam National University in Korea from 2003. In 2001, he received his PhD degree in applied physics from the Tohoku University in Japan. After completing his PhD degree, Soon-Ku performed postdoctoral work at the Brown University. Before starting his PhD degree course, he served for 7 years at Sunkyung and Samsung Companies. His research interests include heteroepitaxy and thin film growth of materials, especially ZnO and GaN, and studies of structural defects and interfaces by TEM. He has authored more than 60 publications in referred intentional journals.