Nitride-based near-ultraviolet multiple-quantum well light-emitting diodes with AlGaN barrier layers

Abstract

The In 0.05 Ga 0.95 N/GaN, In 0.05 Ga 0.95 N/Al 0.1 Ga 0.9 N, and In 0.05 Ga 0.95 N/Al 0.18 Ga 0.82 N multiple-quantum well (MQW) light-emitting diodes (LEDs) were prepared by metal-organic chemical-vapor deposition. (MOCVD). It was found that the 20-mA electroluminescence (EL) intensity of the InGaN/Al 0.1 Ga 0.9 N MQW LED was two times larger than that of the InGaN/GaN MQW LED. The larger maximumoutput intensity and the fact that maximum-output intensity occurred at a larger injection current suggest that Al 0.1 Ga 0.9 N-barrier layers can provide a better carrier confinement and effectively reduce leakage current. In contrast, the EL intensity of the InGaN/Al 0.18 Ga 0.82 N MQW LED was smaller because of the relaxation that occurred in the MQW active region of the sample.