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 $\left(5.3\times {10}^8{\text{cm}}^{-2}\right)$ is as high as 64%. The measured nonradiative coefficient $A$ varies from $6\times {10}^7$ to $2\times {10}^8{\text{s}}^{-1}$ as the dislocation density increases from $5.3\times {10}^8$ to $5.7\times {10}^9{\text{cm}}^{-2}$ , respectively.