MOCVD grown ultraviolet microlight-emitting diodes with an InGaN/GaN/AlGaN active region design

Abstract

In this work, we present an InGaN/GaN/AlGaN active region design for high-efficiency UV LED grown by MOCVD. The use of the GaN layer allows the AlGaN layer to be grown in optimized conditions which will enhance the overall crystal quality and device performance. The InGaN/GaN/AlGaN structure showed an improvement in the internal quantum efficiency (IQE) simulation in comparison with the conventional InGaN/AlGaN structure, with 15% and 14% at operating current density of 20 and 30 A/cm2, respectively. The IQE advantage remains at more than 10% in the operating current density range from 0 to 100 A/cm2 due to an enhanced electron-hole wavefunction overlap. The InGaN/GaN/AlGaN quantum wells were utilized to grow UV-A structures and micro-LEDs with sizes ranging from 20 × 20 to 100 × 100 μm2 were fabricated. The fabricated micro-LEDs showed a reliable emission at around 372 nm with 9 nm FWHM. Micro-LED devices with smaller sizes showed an improvement in relative external quantum efficiency due to its advantage in current spreading. This manuscript presents the potential to achieve both improved crystal quality and high-efficiency device using InGaN/GaN/AlGaN active region design.