High-quality InN films on GaN using graded InGaN buffers by MBE

The growth of high-quality thick InN films is challenging because of the lack of native substrates. In this work, we demonstrate the use of a linearly graded InGaN buffer layer for the growth of InN films on GaN substrates. A 500nm InN film with <0.1nm RMS roughness is obtained with a peak mobility of 1410 cm(2)/(V.s) at 300 K. A strong room temperature photoluminescence showing a bandgap of 0.65 eV with 79meV linewidth is observed. A graded InGaN buffer is found to lead to extremely smooth and high-quality InN films. (C) 2016 The Japan Society of Applied Physics