Thermal stability of emission from single InGaAs/GaAs quantum dots at the telecom O-band

TL;DR

This study investigates the thermal stability of single-photon emission from InGaAs/GaAs quantum dots emitting in the telecom O-band, demonstrating promising operation up to 80 K and 50 K for photon purity, relevant for quantum communication.

Contribution

It provides the first temperature-dependent analysis of telecom-band quantum dot emission, revealing mechanisms to enhance thermal stability and single-photon purity at elevated temperatures.

Findings

Single-photon emission remains pure up to 50 K with $g^{(2)}(0)=0.13$.

Carrier trapping near quantum dots enhances emission at higher temperatures.

Luminescence quenching is mainly due to holes being promoted to higher valence band states.

Abstract

Single-photon sources are key building blocks in most of the emerging secure telecommunication and quantum information processing schemes. Semiconductor quantum dots (QD) have been proven to be the most prospective candidates. However, their practical use in fiber-based quantum communication depends heavily on the possibility of operation in the telecom bands and at temperatures not requiring extensive cryogenic systems. In this paper we present a temperature-dependent study on single QD emission and single-photon emission from metalorganic vapour-phase epitaxy-grown InGaAs/GaAs QDs emitting in the telecom O-band. Micro-photoluminescence studies reveal that trapped holes in the vicinity of a QD act as reservoir of carriers that can be exploited to enhance photoluminescence from trion states observed at elevated temperatures up to at least 80 K. The luminescence quenching is mainly related to the promotion of holes to higher states in the valence band and this aspect must be primarily addressed in order to further increase the thermal stability of emission. Photon autocorrelation measurements yield single photon emission with a purity of $g_{50\mathrm{K}}^{(2)}\left(0\right)=0.13$ up to 50 K. Our results imply that these nanostructures are very promising candidates for single-photon sources at elevated temperatures in the telecom O-band and highlight means for improvements in their performance.