The features of recombination radiation in quantum dots with an (A+ + e) impurity complex in an external electric field. Part 2. Quantum size Stark effect in the recombination emission spectra of quantum dots with an (A+ + e) impurity complex

Abstract

Background. Interest in the optical properties of quantum dots (QD) with (A+ + e) impurity complexes is associated with the possibility of creating new elements of semiconductor optoelectronics based on such structures. In this case, the high sensitivity of the band structure and the energy of impurity states in QD to an external electric field opens up possibilities for controlling the spectra of recombination radiation in impurity complexes. The purpose of this research is to study the effect of an external electric field on radiative recombination in the (A+ + e) impurity complex in semiconductor QD. Materials and methods. The calculation of the spectral recombination radiation intensity (SRRI) in a quantum dot with (A+ + e) impurity complexes in an external electric field was performed in the dipole approximation. The influence of the electric field on the ground state of an electron in a QD was taken into account in the second order of the perturbation theory. The spectral curves of the SRRI, as well as the dependences of the SRRI on the strength of the external electric field, were plotted for QD based on InSb. Results. In the dipole approximation, the SRRI was calculated taking into account 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 to describe the interaction of a hole localized at the A+ center with an electron localized in the ground state of the QD. It is shown that a significant change in SRRI occurs due to a decrease in the overlap integral of the wave functions of an electron and a hole localized at the A+ center due to the electron-hole polarization. It is shown that the asymmetry of the adiabatic potential minimum position in an electric field leads to a nontrivial dependence of the SRRI on the coordinates of the A+ center: when the impurity center approaches the QD boundary, the SRRI maximum shifts to the short-wavelength region of the spectrum, and an increase in the electric field strength leads to a significant drop in the radiation intensity and a shift of its maximum to the long-wavelength region of the spectrum (quantum size Stark effect). Conclusions. In an electric field, efficient control of SIRI with the participation of the (A+ + e) impurity complexes is possible due to the modification of the electronic adiabatic potential.

Keywords

• quantum dot
• impurity complex
• zero radius potential method
• adiabatic approximation
• quantum size stark effect
• spectral recombination radiation intensity
• electron adiabatic potential