400-nm InGaN-GaN and InGaN-AlGaN multiquantum well light-emitting diodes

The 400-nm In0.05Ga0.95N-GaN MQW light-emitting diode (LED) structure and In0.05Ga0.95N-Al0.1Ga0.9N LED structure were both prepared by organometallic vapor phase epitaxy. It was found that the use of Al0.1Ga0.9N as the material for barrier layers would not degrade crystal quality of the epitaxial layers. It was also found that the 20-mA electroluminescence intensity of InGaN-AlGaN multiquantum well (MQW) LED was two times larger than that of the InGaN-GaN MQW LED. The larger maximum output intensity and the fact that maximum output intensity occurred at larger injection current suggest that AlGaN barrier layers can provide a better carrier confinement and effectively reduce leakage current.