Study of (Al, Ga)N bragg mirrors grown on Al2O3(0001) and Si(111) by metalorganic vapor phase epitaxy

A series of selective (Al,Ga)N quarter-wave reflectors has been grown on sapphire and silicon substrates by metalorganic vapor phase epitaxy. The microstructure of the mirror structures, consisting of GaN quarter-wave layers alternating with AlN. AIGaN or AlN/GaN short-period superlattices, has been assessed in terms of a joint X-ray diffraction (XRD) and transmission electron microscopy (TEM) study.