Interwell inhomogeneity of carrier injection in InGaN/GaN/AlGaN multiquantum well lasers

A simulation of current flow for an InGaN/GaN/AlGaN multiquantum well (MQW) laser showed that generation of the optical gain is inhomogeneous across the MQW due to inhomogeneous carrier injection. Laser diodes with three and five wells in MQW were compared to experimentally investigate inhomogeneous carrier injection. We found that external quantum efficiency was significantly improved by a reduction in the number of wells from five to three. The result was explained quantitatively by the fact that the five-well laser had a larger internal loss and a poorer internal quantum efficiency due to the inhomogeneous carrier injection.