# Monolithic III–V membrane photonic crystal lasers on SOI using selective lateral heteroepitaxy

## TL;DR

This paper introduces a new method for making compact and efficient photonic crystal lasers on silicon chips using a novel growth technique.

## Contribution

The paper presents a novel fabrication approach using selective lateral heteroepitaxy to create monolithic III–V membrane photonic crystal lasers on SOI.

## Key findings

- Monolithic III–V membrane photonic crystal lasers on SOI were demonstrated with high mechanical stability and pumping efficiency.
- Room-temperature lasing was achieved at 910 nm and 1430 nm with low thresholds of 17.5 μJ/cm² and 5.7 μJ/cm², respectively.

## Abstract

III–V photonic crystal (PhC) lasers with small footprints and low power consumption are potential ultra-compact and power-efficient light sources for future on-chip optical interconnects. Conventional PhC lasers fabricated by vertical epitaxy require suspended air-bridge structures and air holes etched through the gain medium, severely compromising mechanical resistance to external impacts and pumping efficiency. While bonding and regrowth can mitigate these issues, their fabrication complexity substantially increases process costs and hinders mass production. Here, we address these issues using selective lateral heteroepitaxy and demonstrate monolithically integrated III–V membrane PhC lasers on (001) silicon-on-insulator (SOI). By leveraging selective lateral heteroepitaxy and metal organic chemical vapor deposition (MOCVD), we achieved the growth of dislocation-free InP membranes on SOI wafers patterned in Si-photonics foundries. The unique III-V-on-insulator avoids the formation of air-suspended structures and significantly enhances the mechanical stability of the devices. We also precisely positioned the laterally grown InGaAs/InP quantum wells (QWs) at the center of the InP membrane to avoid etching air holes through the gain medium, thus eliminating surface recombination and drastically improving pumping efficiency. We fabricated near-infrared and telecom PhC lasers using laterally grown III–V membranes, and achieved room-temperature lasing at 910 nm and 1430 nm with low thresholds of 17.5 μJ/cm² and 5.7 μJ/cm², respectively. Our results establish a novel approach for fabricating PhC lasers and provide an elegant solution for monolithically integrated PhC lasers in next-generation optical interconnects.

We demonstrated monolithic III–V membrane photonic crystal (PhC) lasers on SOI using selective lateral heteroepitaxy, which enables high mechanical resistance to external impacts and high pumping efficiency within novel fabrication platform of monolithic III–V PhC lasers for Si photonics.