High-quality InN film grown on a low-temperature-grown GaN intermediate layer by plasma-assisted molecular-beam epitaxy

High-quality indium nitride (InN) films were grown on sapphire substrates by plasma-assisted molecular-beam epitaxy. The structural and electrical properties of the InN films were greatly improved by employing a buffer layer formed with a low-temperature-grown GaN intermediate layer and a low-temperature-grown InN layer. The surface morphology of the InN film was quite smooth - the root-mean-square roughness was less than 5 run. The room-temperature Hall mobility was 1180 cm(2)/V.s, and the residual electron concentration was 1.6 x 10(18) cm(-3). These results indicate that the InN film almost meets the requirements for application to practical devices.