Multiscale simulations of uni-polar hole transport in (In,Ga)N quantum well systems

TL;DR

This study uses multiscale simulations to analyze how alloy micro-structure fluctuations affect hole transport in (In,Ga)N quantum well systems, revealing that alloy disorder can impair hole mobility, especially when quantum effects are considered.

Contribution

It introduces a multi-scale simulation framework combining atomistic and macroscale models to study alloy fluctuation effects on hole transport in (In,Ga)N quantum wells.

Findings

Alloy fluctuations can reduce hole transport efficiency.

Virtual crystal approximation overestimates hole current.

Quantum corrections significantly influence transport results.

Abstract

Understanding the impact of the alloy micro-structure on carrier transport becomes important when designing III-nitride-based LED structures. In this work, we study the impact of alloy fluctuations on the hole carrier transport in (In,Ga)N single and multi-quantum well systems. To disentangle hole transport from electron transport and carrier recombination processes, we focus our attention on uni-polar (p-i-p) systems. The calculations employ our recently established multi-scale simulation framework that connects atomistic tight-binding theory with a macroscale drift-diffusion model. In addition to alloy fluctuations, we pay special attention to the impact of quantum corrections on hole transport. Our calculations indicate that results from a virtual crystal approximation present an upper limit for the hole transport in a p-i-p structure in terms of the current-voltage characteristics. Thus we find that alloy fluctuations can have a detrimental effect on hole transport in (In,Ga)N quantum well systems, in contrast to uni-polar electron transport. However, our studies also reveal that the magnitude by which the random alloy results deviate from virtual crystal approximation data depends on several factors, e.g. how quantum corrections are treated in the transport calculations.