Exciton complexes assisted transition channels in the optically excited single-electron tunneling units

Abstract

The emission spectrum from the optically excited single electron tunneling devices, electrostatically coupled to a p-type side quantum dot, has been investigated. The 12 exciton-complexes transition processes have been found and can be classified into six electron-like and six hole-like transition processes. The self-consistent numerical analysis shows that the gate and bias voltages can be tuned to change the weight functions associated with the particular exciton-complexes transition processes, thereby influencing the intensity and frequency-dependence of the spontaneous emission signals. The energy discrepancies up to the quadratic terms with respect to bias voltages are taken into account to interpret different degrees of the Stark shifts experienced by the electron and the hole. There exist several competition mechanisms, where the increase of the gate voltage can neutralize the shift to lower-energy transition channels produced by the increase of the hole occupancy in the side dot, and the interdot repulsive and attractive Coulombic blockades compete with each other to determine the superiority or inferiority of the different resonance channels. The electron-like resonance channels can be switched to the hole-like ones or vice versa in the optical spectra by tuning the gate voltages.