Novel staggered quantum well design and in-surfactant GaN buffer layer in UVA light emitting diode heterostructures

Abstract

We propose a novel symmetric InGaN staggered quantum well (SQW) design for the growth of an InGaN/GaN UVA LED heterostructure, aiming at improving carriers’ confinement in the multi-quantum well (MQW) active region of the LED, especially at higher currents. In comparison to conventional methods, the SQW was inserted only in the last two QWs to shorten the overall growth time. Additionally, indium-surfactant was introduced during the growth of GaN buffer layer (In-surfactant GaN buffer layer) as an effort to improve the MQW growth further. With respect to the reference LED, i.e. without the SQW and the In-surfactant GaN buffer layer, the crystalline and surface properties improve for the LED with both SQW and In-surfactant GaN buffer layer. Moreover, the forward voltage can be as low as 3.23 V and the output power reaches approximately 25 mW at 100 mA with the SQW and In-surfactant GaN buffer layer.