Influence of polarity on carrier transport in semipolar (20(21)over-bar) and (20(2)over-bar1) 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 (20 (2) over bar1) and (20 (21) over bar) 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 (20 (21) over bar) MQW LEDs with the same polarity to Ga-polar c-plane LEDs have a more uniform carrier distribution and lower forward voltage than (20 (2) over bar1) MQW LEDs. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4726106]