The impact of purging on the quality of AlGaN/GaN multiple quantum wells grown on AlN/sapphire template

Abstract

The ultraviolet (UV) emitting AlGaN/GaN multiple quantum wells (MQWs) were grown on low dislocation density AlN/sapphire templates by metal-organic chemical vapor deposition (MOCVD). The impact of the purg time on the interface quality of the AlGaN/GaN quantum well was studied. The high resolution x-ray diffraction (XRD) measurement results demonstrate that the density of dislocations was reduced significantly with the purge time after growth of AlGaN barrier layer and GaN well layer was determined to be 4 min and 2 min, respectively. The mechanism of defect formation in quantum wells was investigated by scanning electron microscope (SEM) measurement.