The role of dislocations as nonradiative recombination centers in InGaN quantum wells

InGaN multiple quantum wells (MQWs) were grown on atomically smooth c-GaN templates and identical c-GaN templates etched to reveal hexagonal pits associated with screw dislocations. We found that the room temperature internal quantum efficiency of the MQWs grown on the etched c-GaN templates is a factor of 2 higher than that of the smooth QWs. This finding is accounted for by the fact that the QWs on the nonplanar surfaces are thinner than the c-plane QWs, and thus the carriers are prevented from reaching the dislocations due to the energy barrier around each defect.