Photon emission by hot electron injection across a lateral pn junction

We demonstrate a method to generate photons by injecting hot electrons into a { pn} junction within a {GaAs/AlGaAs} heterostructure. Hot electrons are generated by biasing across a mesoscopic potential in { n}-type region and travel toward { p}-type region through quantum Hall edge channel in the presence of magnetic field perpendicular to the substrate. The { 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 { p}-type region and to recombine with induced holes followed by photon emissions. Hot electron-induced hole recombination is confirmed by a peak around {810}{nm} in an optical spectrum that corresponds to excitonic recombination in a {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.