Optical properties of GaAs/Al_{x}Ga_{1-x}As/GaAs quantum dot with off-central impurity driven by electric field

Holovatsky Holovatsky,Voitsekhivska Voitsekhivska,Yakhnevych Yakhnevych

doi:10.5488/cmp.21.13703

Abstract

The effect of a constant electric field and donor impurity on the energies and oscillator strengths of electron intraband quantum transitions in double-well spherical quantum dot GaAs/Al$_{x}$Ga$_{1-x}$As/GaAs is researched. The problem is solved in the framework of the effective mass approximation and rectangular potential wells and barriers model using the method of wave function expansion over a complete set of electron wave functions in nanostructure without electric field. It is shown that under the effect of electric field, the electron in the ground state tunnels from the inner potential well into the outer one. It also influences on the oscillator strengths of intraband quantum transition. The binding energy of an electron with ion impurity is obtained as a function of electric field intensity at a different location of impurity.

Highlights

Multishell quantum dots (QDs) are new and very interesting objects of research in nanostructure physics
The computer calculations were performed using the physical parameters of AlxGa1−xAs semiconductor with Al concentration x = 0 for the potential wells and x = 0.4 for the barriers, m0 = 0.067me, m1 = 0.1me, V = 297 meV, ε1 = 13.2, ε2 = 11.9, ε3 = 1, where me is the mass of a pure electron
When the electric field intensity increases and the impurity shifts from QD center, the number of states |n m, which make a significant contribution into ψjm(rì), increases

Summary

Introduction

Multishell quantum dots (QDs) are new and very interesting objects of research in nanostructure physics. In [18], the influence of central impurity and external electric field on the energies of intraband quantum transitions and absorption coefficient is studied in spherical quantum dot CdTe/ZnTe. The effect of impurity on the energy spectra in multishell nanostructures is researched within different methods in [19,20,21,22,23,24,25]. The effect of electric field on quasi-particles energy spectra in spherical nanostructures with one potential well is investigated in [18, 26, 27]. The oscillator strengths of intraband quantum transitions and binding energy of electron with donor impurity are calculated at its different location

Theoretical model

Results and discussion

Summary