Epitaxial growth of high-quality InN films on sapphire substrates by plasma-assisted molecular-beam epitaxy

Abstract

Studying the epitaxial growth of InN films by plasma-assisted molecular-beam epitaxy, we found a buffer layer formed with a low-temperature-grown GaN (LT-GaN) and a low-temperature-grown InN (LT-InN) layers to be effective for improving their structural and electrical properties. Not only the growth temperature of a main part of InN film but growth temperatures and thicknesses of LT-GaN and LT-InN layers strongly influenced InN film properties. The surface of a 260-nm-thick InN film grown at the optimum condition was smooth with the surface root-mean-square roughness less than 4 nm. Its Hall mobility and background electron density at room temperature were 1420 cm 2/ V s and 1.4×10 18 cm −3 , respectively.