Reduction of Efficiency Droop in Semipolar (1(1)over-bar01) InGaN/GaN Light Emitting Diodes Grown on Patterned Silicon Substrates

Abstract

We present a study of semi-polar (1 (1) over bar 01) InGaN-based light emitting diodes (LEDs) grown on patterned (001) Si substrates by atmospheric-pressure metal organic chemical vapor deposition. A transmission electron microscopy image of the semi-polar template shows that the threading dislocation density was decreased significantly. From electroluminescence measurement, semi-polar LEDs exhibit little blue-shift and low efficiency droop at a high injection current because the reduction of the polarization field not only made the band diagram smoother but also restricted electron overflow to the p-GaN layer as shown in simulations. These results indicate that semi-polar InGaN-based LEDs can possess a high radiative recombination rate and low efficiency droop at a high injection current. (C) 2011 The Japan Society of Applied Physics