Improvement of Electrical Properties in ZnO Thin Films Grown by Radical Source(RS)-MBE

Abstract

We grew high quality ZnO crystal on a-plane sapphire substrates by RS(radical source)-MBE. Oxygen polarity (–c) ZnO, which has a flat and smooth surface, was obtained under Zn rich conditions at the initial growth of low temperature buffer layer. High Zn flux is required to grow ZnO at high temperature and form the –c polarity. The high temperature ZnO growth has made possible the improvement of ZnO electrical properties. ZnO epilayers with electron mobilities of 120 cm2/Vs and electron concentrations of 7 × 1016 cm–3 were grown.