Specific Features of Recombination Radiation in Quantum Dots with the A⁺ + e Impurity Complexes in the Presence of External Electric Field. Part II. Quantum-Size Stark Effect in the Spectra of Recombination Radiation of Quantum Dots with the A⁺ + e Impurity Complex

Abstract

Interest in the optical properties of quantum dots (QDs) with the ${{A}^{ + }} + e$ impurity complexes is due to the possibility of construction of new elements of semiconductor optoelectronics based on such structures. Relatively high sensitivity of the band structure and energy of impurity states in QDs to an external electric field opens up prospects for control of the spectra of recombination radiation with the aid of impurity centers. The purpose of this work is to theoretically study the effect of external electric field on radiative recombination in the ${{A}^{ + }} + e$ impurity complex in semiconductor QDs. The spectral intensity of recombination radiation (SIRR) in a quantum dot with the ${{A}^{ + }} + e$ impurity complexes in the presence of external electric field is calculated in the dipole approximation. The effect of the electric field on the ground state of electron in a QD is taken into account in the second order of the perturbation theory. The SIRR spectral curves and the dependences of the SIRR on the strength of the external electric field are plotted for QDs based on InSb. The SIRR is calculated in the dipole approximation with allowance for the Lorentz broadening of energy levels in QD with the ${{A}^{ + }} + e$ impurity complex. The calculation is based on the use of the adiabatic approximation in the analysis of the interaction of a hole localized at the A⁺ center with an electron localized on the ground state of the QD. It is shown that a significant variation in the SIRR is caused by a decrease in the overlap integral of the wave functions of electron and hole localized at the A⁺ center due to the electron–hole polarization. It is also shown that the asymmetry of the position of the minimum of the adiabatic potential in the presence of electric field leads to a nontrivial dependence of the SIRR on the coordinates of the A⁺ center: when the impurity center approaches the boundary of the QD, the SIRR maximum is blue-shifted, and an increase in the electric field strength leads to a significant decrease in the radiation intensity and a red shift of its maximum (quantum-size Stark effect). In the presence of electric field, the SIRR can efficiently be controlled with the aid of the ${{A}^{ + }} + e$ impurity complexes due to the modification of the electron adiabatic potential.