High luminescent efficiency of InGaN multiple quantum wells grown on InGaN underlying layers

InGaN multiple quantum wells were grown on InGaN underlying layers 50 nm thick by metalorganic vapor phase epitaxy. Photoluminescence (PL) measurements were performed by selective excitation of the quantum wells under a weak excitation condition. The PL intensity was almost constant at temperatures ranging from 17 to 150 K. Assuming that the internal quantum efficiency $\left({\eta }_{\mathrm{int}}\right)$ equals unity at 17 K, we obtained ${\eta }_{\mathrm{int}}$ as high as 0.71 even at room temperature. The reason for the high ${\eta }_{\mathrm{int}}$ is the reduction of nonradiative recombination centers by the incorporation of indium atoms into the underlying layer.