Deep ultraviolet emitting AlGaN quantum wells with high internal quantum efficiency

We report the development of Al0.7Ga0.3N/AlN quantum wells with high internal quantum efficiency. All samples had identical well and barrier thickness but the III/V flux ratio was varied during growth by increasing the Ga flux. The luminescence spectra show single peaks which vary from 220 nm (III/V∼1) to 250 nm (III/V⪢1) with internal quantum efficiency varying from 5% to 50%, respectively. To account for these results, a growth model was proposed in which at III/V∼1 the growth proceeds via vapor phase epitaxy, while at III/V⪢1 the growth proceeds via liquid phase epitaxy.