Effects of V/III supply ratio on improvement of crystal quality of zincblende GaN grown by gas source molecular beam epitaxy using RF-radical nitrogen source

Abstract

The effects of the V/III supply ratio on the crystal quality of zincblende GaN grown on (001) GaAs substrates by gas source molecular beam epitaxy, using a 13.56 MHz RF-radical nitrogen source, was investigated. The surface morphology was drastically improved by optimizing the V/III ratio, resulting in a featureless smooth surface. The measured electron concentration increased with increasing the V/III supply ratio. This phenomenon is explained by the electrons originating from nitrogen vacancies being compensated by defects due to the poor crystal quality of GaN grown at lower V/III supply ratios.