Investigation of optimum growth conditions of InAlN for application in distributed Bragg reflectors

Abstract

InxAl1−xN is an alloy system which can be lattice matched to GaN, with many potential applications including distributed Bragg reflectors. This work investigated the effect of changing the ammonia flux during metal organic vapour phase epitaxy growth. The indium incorporation increases as the ammonia flux is increased from 44.6 mmol/min to 179 mmol/min, but remains constant for further increases up to 446 mmol/min. The surfaces across this range generally have low surface roughnesses suitable for use in distributed Bragg reflectors. However, some samples have significant surface pit densities, although these are not linked to similar rises in threading dislocations generated at the GaN / InAlN interface.