Phase separation in bulk InGaN and quantum wells grown by low pressure MOCVD

Abstract

We have grown high quality InGaN layers and InGaN/GaN multiple quantum wells for blue LED applications. The degree of phase segregation of InGaN in bulk InGaN layers depends on the TMI and TMG flow rates as well as the growth temperature. Even for films without indium droplets on the surface, X-ray diffraction (XRD) reveals the coexistence of different indium compositions in the films. In this case photoluminescence of the films is red-shifted with respect to the wavelength calculated using the indium composition determined by XRD. The same observation is made for the multiple quantum wells, where phase segregation can significantly reduce interface abruptness.