Carrier recombination dynamics in InGaN/GaN multiple quantum wells

TL;DR

This study investigates carrier recombination in InGaN/GaN quantum wells, revealing biphasic dynamics with exponential short-time and power-law long-time behaviors, explained by a three-level charge transfer model involving localized states.

Contribution

Introduces a three-level model to explain biphasic recombination dynamics in InGaN/GaN quantum wells, highlighting the role of localized charge-separated states.

Findings

Recombination follows exponential decay at <30 ns

Power-law decay observed at >1 μs

Charge transfer occurs via tunneling between localized states

Abstract

We have mesured the carrier recombination dynamics in InGaN/GaN multiple quantum wells over an unprecedented range in intensity. We find that at times shorter than 30\,ns, they follow an exponential form, and a power law at times longer than 1\,$\mu$s. To explain these biphasic dynamics, we propose a simple three-level model where a charge-separated state interplays with the radiative state through charge transfer following a tunneling mechanism. We show how the distribution of distances in charge-separated states controls the dynamics at long time. Our results imply that charge recombination happens on nearly-isolated clusters of localization centers.