Carrier Transport in Electrically-Driven Photonic Crystal Membrane Lasers

TL;DR

This paper models carrier transport in photonic crystal membrane lasers with lateral current injection, revealing leakage paths and their impact on efficiency, and highlights the importance of p-region design for optimal performance.

Contribution

It introduces a 2D finite-volume simulation model to analyze carrier leakage and injection efficiency in photonic crystal lasers, aiding design optimization.

Findings

Leakage paths reduce injection efficiency and cause spontaneous recombination.

Spatial p-region profile critically affects injection efficiency.

Model explains experimental low injection efficiencies.

Abstract

We model carrier transport in photonic crystal lasers with lateral current injection through two-dimensional (2D) finite-volume simulations. Though such lasers can achieve ultra-low threshold currents, leakage paths reduce the carrier injection efficiency. The design is evaluated through its performance in terms of injection efficiency, internal quantum efficiency, and IV characteristics. Our model predicts the presence of unconventional leakage paths, explaining experimental observations of low injection efficiencies and enhanced spontaneous recombination at doping interfaces. Carrier leakage paths arise due to insufficient injection of holes into the active region, leading to an electric field that increases the energy barrier for electrons, thereby reducing the injection efficiency. The spatial profile of the p-doped region is shown to play a critical role in achieving a high electrical injection efficiency and low-threshold lasing. The model is an important step towards modelling and optimizing properties of 2D photonic crystal membrane lasers.