Void Engineering in Epitaxially Regrown GaAs-Based Photonic Crystal Surface Emitting Lasers by Grating Profile Design

TL;DR

This paper demonstrates how engineering air-voids in GaAs-based photonic crystal surface emitting lasers via grating profile design can significantly improve laser performance by reducing threshold current and increasing output power.

Contribution

It introduces a novel method of void engineering through grating profile modification during epitaxial regrowth, enhancing laser efficiency.

Findings

Void volume increase reduces threshold current.

Enhanced grating coupling boosts output power.

Void formation mechanism elucidated via electron microscopy.

Abstract

We report the engineering of air-voids embedded in GaAs-based photonic crystal surface emitting lasers realised by metalorganic vapour-phase epitaxy regrowth. Two distinct void geometries are obtained by modifying the photonic crystal grating profile within the reactor prior to regrowth. The mechanism of void formation is inferred from scanning transmission electron microscopy analysis, with the evolution of the growth front illustrated though the use of an AlAs/GaAs superlattice structure. Competition between rapid lateral growth of the (100) surface and slow diffusion across higher index planes is exploited in order to increase void volume, leading to an order of magnitude reduction in threshold current and an increase in output power through an increase in the associated grating coupling strength.