Photon emission by hot electron injection across a lateral \textit{pn} junction

TL;DR

This paper presents a novel method to generate photons by injecting hot electrons across a extit{pn} junction in a GaAs/AlGaAs heterostructure, utilizing quantum Hall edge channels and surface gating to enable controlled electron-hole recombination.

Contribution

The authors demonstrate a new technique to produce photons via hot electron injection and suppression of energy relaxation, advancing quantum optoelectronic device development.

Findings

Photon emission confirmed at 810 nm wavelength.

Asymmetric optical spectrum due to chiral electron transport.

Potential for on-demand single-photon source development.

Abstract

We demonstrate a method to generate photons by injecting hot electrons into a {\it pn} junction within a \ce{GaAs/AlGaAs} heterostructure. Hot electrons are generated by biasing across a mesoscopic potential in {\it n}-type region and travel toward {\it p}-type region through quantum Hall edge channel in the presence of magnetic field perpendicular to the substrate. The {\it p}-type region is created several microns away from the hot electron emitter by inducing interfacial charges using a surface gate. The energy relaxation of the hot electrons is suppressed by separating the orbitals before and after longitudinal-optical (LO) phonon emission. This technique enables the hot electrons to reach the {\it p}-type region and to recombine with induced holes followed by photon emissions. Hot electron-induced hole recombination is confirmed by a peak around \qty{810}{nm} in an optical spectrum that corresponds to excitonic recombination in a \ce{GaAs} quantum well. An asymmetric structure observed in the optical spectrum as a function of the magnetic field originates from the chiral transport of the hot electrons in the Hall edge channel. We propose the combination of our technology and on-demand single-electron source would enable the development of an on-demand single photon source that is an essential building block to drive an optical quantum circuit and to transfer quantum information for a long distance.