Abstract
High-quality single-crystal Gd2O3 nano films have been grown epitaxially on GaN (0001). The films were electron beam evaporated from powder-packed and sintered Gd2O3 target at a substrate temperature of 700°C by molecular beam epitaxy (MBE).Structural studies were carried out by x-ray diffraction using a synchrotron radiation source, and cross sectional high-resolution transmission electron microscopy (HRTEM). The growth was in-situ monitored by reflection high energy electron diffraction. Electrical measurements of I-V andC-V characteristics were also carried out.The films adopt the high temperature monoclinic phase with six domains. The films are well aligned with theGaN substrate with an orientation relationship ofGd2O3 (012)m // GaN (0001), and a dominant in-plane expitaxy of Gd2O3 [020]m // GaN [1120]. Excellent leakage performance (JL~4.6x10-9 A/cm2 at 1MV/cm) is observed after 1100oC RTP, possibly due to a significant domain size increase by ~ 3 times as revealed by grazing incidence x-ray diffraction data together with the Williamson-Hall plot analysis.