Internal quantum efficiency and nonradiative recombination coefficient of GaInN/GaN multiple quantum wells with different dislocation densities

Abstract

Room-temperature photoluminescence (PL) measurements are performed on GaInN/GaN multiple-quantum-well heterostructures grown on GaN-on-sapphire templates with different threading-dislocation densities. The selective optical excitation of quantum wells and the dependence of integrated PL intensity on excitation power allow us to determine the internal quantum efficiency (IQE) as a function of carrier concentration. The measured IQE of the sample with the lowest dislocation density (5.3x10(8) cm(-2)) is as high as 64%. The measured nonradiative coefficient A varies from 6x10(7) to 2x10(8) s(-1) as the dislocation density increases from 5.3x10(8) to 5.7x10(9) cm(-2), respectively.