Blue-light emission from molecular-beam-epitaxially grown GaN/Al0.5Ga0.5N multiple quantum wells with a perturbating layer of Al0.5Ga0.5N monolayers

We have studied the influence of AlGaN inserting layer into GaN well region on the light emission from a strained GaN/AlGaN multiple-quantum-well system. We have found that, by simply inserting thin AlGaN layer, the luminescence is dramatically redshifted with respect to that of the normal GaN/AlGaN quantum well, which is centered at 2.96 eV, nearly 0.52 eV below the bulk GaN band gap. We attribute this enormous redshift to an additional 0.7 MV/cm field present in the well due to the perturbation of the well region by inserting AlGaN layer. The result is revealed to be of great importance in the design and analysis of nitride heterostructure devices which can be exploited to advantage in nitride materials and device engineering