Numerical analysis of efficiency droop induced by piezoelectric polarization in InGaN/GaN light-emitting diodes

Abstract

The effects of piezoelectric polarization on efficiency droop in InGaN/GaN light-emitting diodes (LEDs) have been investigated using numerical analysis. The simulation results showed that the severe band bending in InGaN quantum-well was improved as the piezoelectric polarization is reduced, resulting in the improved overlap of electron and hole wave functions. As a results, the internal quantum efficiency increases and efficiency droop significantly reduces. The reduction in piezoelectric polarization could be derived by applying a tensile stress to relax compressive stress in GaN epilayer, improving the efficiency droop of vertical-structure LEDs, agree well with simulation ones. (C) 2010 American Institute of Physics. [doi:10.1063/1.3464976]