Improvements of quantum efficiency and thermal stability by using Si delta doping in blue InGaN/GaN multiple quantum well light‐emitting diodes

Abstract

AbstractThe improvements of quantum efficiency and thermal stability by using Si delta doping in blue InGaN/GaN multiple quantum well (MQW) structures have been investigated. The high‐resolution X‐ray diffraction (HR‐XRD) indicated better interface properties in the MQWs for Si delta doping structures. The Arrhenius plots of the temperature‐dependent photoluminescence (PL) spectra were used to reveal the enhancements of the radiative recombination. The activation energy was increased from 115 to 140 meV for the InGaN/GaN MQW sample with Si delta doping. The improvements of the thermal stability and activation energy were attributed to the supply of electrons from the Si delta doping barrier region into the InGaN well layer and the increase in hole capturing by the higher energy barrier in the valence band. Si delta doping process plays a crucial role in carrier recombination to significantly suppress carrier leakage, which not only increases the exciton confinement, but also improves the quantum efficiency. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)