Influence of polarity on carrier transport in semipolar (2021¯) and (202¯1) multiple-quantum-well light-emitting diodes

We investigate the influence of polarity on carrier transport in single-quantum-well and multiple-quantum-well (MQW) light-emitting diodes (LEDs) grown on the semipolar (202¯1) and (2021¯) orientations of free-standing GaN. For semipolar MQW LEDs with the opposite polarity to conventional Ga-polar c-plane LEDs, the polarization-related electric field in the QWs results in an additional energy barrier for carriers to escape the QWs. We show that semipolar (2021¯) MQW LEDs with the same polarity to Ga-polar c-plane LEDs have a more uniform carrier distribution and lower forward voltage than (202¯1) MQW LEDs.