Thin-Film InGaAs Metamorphic Buffer for telecom C-band InAs Quantum Dots and Optical Resonators on GaAs Platform

TL;DR

This paper introduces a novel thin-film InGaAs metamorphic buffer for GaAs-based quantum dot devices, enabling emission at telecom wavelengths and integration into photonic resonators, advancing quantum communication technologies.

Contribution

It presents a new non-linear indium grading profile for InGaAs buffers that allows for thinner, more compatible metamorphic layers on GaAs, facilitating telecom-range quantum dot emission.

Findings

Demonstrated single-photon emission at 1550nm from InAs QDs on the new buffer

Successfully integrated the buffer into a bullseye cavity for photonic applications

Proved the buffer's effectiveness in enabling telecom-range quantum light sources

Abstract

The GaAs-based material system is well-known for the implementation of InAs quantum dots (QDs) with outstanding optical properties. However, these dots typically emit at a wavelength of around 900nm. The insertion of a metamorphic buffer (MMB) can shift the emission to the technologically attractive telecom C-band range centered at 1550nm. However, the thickness of common MMB designs limits their compatibility with most photonic resonator types. Here we report on the MOVPE growth of a novel InGaAs MMB with a non-linear indium content grading profile designed to maximize plastic relaxation within minimal layer thickness. Single-photon emission at 1550nm from InAs QDs deposited on top of this thin-film MMB is demonstrated. The strength of the new design is proven by integrating it into a bullseye cavity via nano-structuring techniques. The presented advances in the epitaxial growth of QD/MMB structures form the basis for the fabrication of high-quality telecom non-classical light sources as a key component of photonic quantum technologies.