Impact of carrier localization on recombination in InGaN quantum wells and the efficiency of nitride light-emitting diodes: insights from theory and numerical simulations

TL;DR

This study uses theory and simulations to show that carrier localization in InGaN quantum wells increases recombination rates, negatively impacting the efficiency of nitride LEDs, especially in green emission ranges.

Contribution

It provides a detailed analysis of how alloy fluctuations influence recombination processes and LED efficiency, combining theoretical insights with numerical simulations.

Findings

Localization increases both radiative and Auger recombination rates.

Auger recombination rates increase more significantly than radiative rates due to localization.

Localization worsens efficiency droop and green-gap issues in InGaN LEDs.

Abstract

We examine the effect of carrier localization due to random alloy fluctuations on the radiative and Auger recombination rates in InGaN quantum wells as a function of alloy composition, crystal orientation, carrier density, and temperature. Our results show that alloy fluctuations reduce individual transition matrix elements by the separate localization of electrons and holes, but this effect is overcompensated by the additional transitions enabled by translational symmetry breaking and the resulting lack of momentum conservation. Hence, we find that localization increases both radiative and Auger recombination rates, but that Auger recombination rates increase by one order of magnitude more than radiative rates. Furthermore, we demonstrate that localization has an overall detrimental effect on the efficiency-droop and green-gap problems of InGaN LEDs.