Luminescence Dynamics and Structural Investigation of InGaN/GaN Multiple Quantum Well Light Emitting Diodes

Abstract

Luminescence properties of blue emission InGaN/GaN multiple quantum well (MQW) have been studied by temperature dependent photoluminescence (PL), photoluminescence excitation (PLE) and time-resolved photoluminescence (TRPL) spectroscopic techniques. Two typical samples are studied, both consisting of five periods of InGaN wells with different indium compositions of 21% and 24%, respectively. According to the PL and PLE measurement results, large values of activation energy and Stokes’ shift are obtained. This indicates that higher Indium composition results in an increase of composition fluctuation in the InGaN MQW region, showing the stronger carrier localization effect. The lifetime at the low-energy side of the InGaN peaks is longer for higher indium composition, as expected from the larger Stokes shift.