Light-emitting current of electrically driven single-photon sources

The time-dependent tunneling current arising from the electron-hole recombination of the exciton state is theoretically studied using the nonequilibrium Green's function technique and the Anderson model with two energy levels. Charge conservation and gauge invariance are satisfied in the tunneling current. Apart from the classical capacitive charging and discharging behavior, tunneling oscillations are superimposed on the tunneling current for applied rectangular pulse voltages.