Gradient Doping of Mg in p-Type GaN for High Efficiency InGaN–GaN Ultraviolet Light-Emitting Diode

The performance of a InGaN-GaN multiple quantum-well (MQW) ultraviolet (UV) light-emitting diode (LED) with an emission of 385 nm was enhanced by a gradient doping of Mg in the p-GaN layer. The optical output power was enhanced by 21% at an input current of 20 mA compared to that of a UV LED with a uniformly doped p-GaN layer. The improved performance of the UV LED could be attributed to the decrease in diffusion of Mg into MQW and the suppression of electron transport from the conduction band of the MQW to the acceptor level of the deep donor acceptor pair bands in the p-GaN layer by a gradient doping of Mg in p-GaN layer.