Ordered arrays of InGaN/GaN dot-in-a-wire nanostructures as single photon emitters

TL;DR

This paper demonstrates the fabrication and characterization of ordered arrays of InGaN/GaN nanostructures that act as reliable, polarized single-photon emitters operable at high temperatures, advancing solid-state quantum light sources.

Contribution

It introduces a new method to create spatially ordered InGaN/GaN nanostructure arrays as efficient, polarized single-photon emitters with potential for high-temperature operation.

Findings

Single-photon emission confirmed by photon antibunching measurements.

Emission covers blue-to-green spectral range with high polarization ratio.

Photon emission rate scales linearly with excitation power.

Abstract

The realization of reliable single photon emitters operating at high temperature and located at predetermined positions still presents a major challenge for the development of solid-state systems for quantum light applications. We demonstrate single-photon emission from two-dimensional ordered arrays of GaN nanowires containing InGaN nano-disks. The structures were fabricated by molecular beam epitaxy on (0001) GaN-on-sapphire templates patterned with nanohole masks prepared by colloidal lithography. Low-temperature cathodoluminescence measurements reveal the spatial distribution of light emitted from a single nanowire heterostructure. The emission originating from the topmost part of the InGaN regions covers the blue-to-green spectral range and shows intense and narrow quantum dot-like photoluminescence lines. These lines exhibit an average linear polarization ratio of 92%. Photon correlation measurements show photon antibunching with a g(2)(0) values well below the 0.5 threshold for single photon emission. The antibunching rate increases linearly with the optical excitation power, extrapolating to the exciton decay rate of ~1 ns-1 at vanishing pump power. This value is comparable with the exciton lifetime measured by time-resolved photoluminescence. Fast and efficient single photon emitters with controlled spatial position and strong linear polarization are an important step towards high-speed on-chip quantum information management.