Efficiency and Droop Improvement in InGaN/GaN Light-Emitting Diodes by Selective Carrier Distribution Manipulation

Efficiency and droop behavior in InGaN/GaN light-emitting diodes (LEDs) are both improved using selectively graded composition multiple quantum barriers (SGQBs). Simulation results show that SGQBs could moderately improve the hole transport in the active region. In the meantime, the spatial distribution overlap between electrons and holes in the active region could also be well considered. Therefore, the radiative recombination of the SGQB LED is more efficient than that of the conventional LED. The overall efficiency and droop behavior are simultaneously improved in the SGQB LED, at both low and high current densities. (C) 2012 The Japan Society of Applied Physics