# Single-photon light emitting diodes based on pre-selected quantum dots using a deterministic lithography technique

## TL;DR

This paper presents a new fabrication process for electrically driven single-photon LEDs based on pre-selected quantum dots, demonstrating single-photon emission with potential for telecom applications.

## Contribution

It introduces a deterministic lithography technique for pre-selecting quantum dots to create efficient, electrically driven single-photon light-emitting diodes with improved performance.

## Key findings

- Single-photon emission observed with g^{(2)}(0)=0.42
- Device operates under electrical injection and pulsed excitation
- Process extendable to wavelengths above 600 nm

## Abstract

In the present study, we developed a fabrication process of an electrically driven single-photon LED based on InP QDs emitting in the red spectral range, the wavelength of interest coinciding with the high efficiency window of Si APDs. A deterministic lithography technique allowed for the pre-selection of a suitable QD, here exclusively operated under electrical carrier injection. The final device was characterized under micro-electroluminescence in direct current, as well as in pulsed excitation mode. In particular, under pulsed excitation of one device, single-photon emission of a spectral line, identified as an exciton, has been observed with $g^{(2)}_\mathrm{raw}(0)=0.42\pm0.02$, where the non-zero $g^{(2)}$-value is mainly caused by background contribution in the spectrum and re-excitation processes due to the electrical pulse length. The obtained results constitute an important step forward in the fabrication of electrically driven single-photon sources, where deterministic lithography techniques can be used to sensibly improve the device performances. In principle, the developed process can be extended to any desired emitter wavelength above $600\,\mathrm{nm}$ up to the telecom bands.