Investigation of the emission mechanism in InGaN/GaN-based light-emitting diodes

Abstract

The exciton-localization effect and quantum-confine Stark effect (QCSE) on the performance of InGaN/GaN-based light-emitting diodes (LEDs) have been investigated with regard to indium mole fraction and well thickness by means of temperature-dependent and excitation-power-dependent photoluminescence measurements. The exciton-localization effect can be enhanced by increasing the indium mole fraction or increasing well thickness but up to 2.5 nm. The QCSE is monotonically enhanced with increasing indium concentration or well thickness. The output power of the LED can be increased by the enhanced exciton-localization effect; however, the QCSE has much stronger influence on the output power of LEDs than the exciton-localization effect, which should be taken into account for further improving the performance of InGaN/GaN-based LEDs.