Ring-shaped luminescence pattern in biased quantum wells studied as a steady state reaction front

TL;DR

This paper investigates the formation of ring-shaped luminescence patterns in biased quantum wells, analyzing the steady-state diffusion-reaction dynamics that produce these patterns and deriving analytic solutions compared to simulations.

Contribution

It provides a detailed analytical and numerical study of the steady-state reaction front in quantum wells, revealing effects of source asymmetry on the pattern formation.

Findings

Asymmetry in carrier sources causes unusual steady-state effects.

Analytic expressions match well with simulation results.

Steady-state interface position depends on source conditions.

Abstract

Under certain conditions, focused laser excitation in semiconductor quantum well structures can lead to charge separation and a circular reaction front, which is visible as a ring-shaped photoluminescence pattern. The diffusion-reaction equations governing the system are studied here with the aim of a detailed understanding of the steady state. The qualitative asymmetry in the sources for the two carriers is found to lead to unusual effects which dramatically affect the steady-state configuration. Analytic expressions are derived for carrier distributions and interface position for a number of cases. These are compared with steady-state information obtained from simulations of the diffusion-reaction equations.