Investigation of Quantum-Well Shapes and Their Impacts on the Performance of InGaN/GaN Light-Emitting Diodes

Abstract

We investigate the impacts of quantum-well (QW) shapes on the performance of InGaN/GaN light-emitting diodes (LEDs) grown on c-plane sapphire substrates. Three different QW shapes are utilized, namely, rectangular, staircase, and trapezoidal QWs of thicknesses of 4, 5, and 6 nm. Various optoelectronic measurements are conducted on these samples to determine the correlation of the effect of piezoelectric field with device performances. It is found that the staircase QW consistently shows the reduced effect of piezoelectric field, which agrees well with the simulation results of the increased electron-hole overlap integral over the conventional rectangular QW. The nonconventional QW can reduce the effect of piezoelectric field and improve the LED performance accordingly. (C) 2013 The Japan Society of Applied Physics