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

The exciton-localization effect and quantum-confine Stark effect (QCSE) on the performance of InGaN/GaN-based light-emitting diodes (LEDs) have been i nvestigated 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. Th e QCSE is monotonically enhanced with increasing indium concentration or we ll 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 sho uld be taken into account for further improving the performance of InGaN/Ga N-based LEDs. (C) 2001 American Institute of Physics.