Effect of magnetic field, size and donor position on the absorption coefficients related a donor within the core/shell/shell quantum dot

E B Al

doi:10.1007/s11082-021-03340-w

Abstract

In this study, linear, nonlinear and total optical absorption coefficients related a single shallow donor atom confined in semiconductor core/shell/shell quantum dot heterostructure are researched in detail within the compact density matrix formalism approximation. For this purpose, firstly, the energies and the wavefunctions are computed by the diagonalization method in the effective mass approach. Moreover, the effects of size modulation, donor position and magnetic field are analyzed. The numerical results indicate that the linear and nonlinear parts of the absorption coefficients related with intersubband \(1s\rightarrow 1p\) and \(1p\rightarrow 1d\) donor transitions undergo significant changes.

Highlights

It is generally accepted that the progress of electronic and opto-electronic devices depends on understanding the basic chemical and physical properties of low-dimensional structures (LDSs)
The effects of magnetic field, geometric confinement and donor position change on optical absorption coefficients (OACs) will be discussed according to the spherical core/shell/shell QD (CSSQD) nanostructure model outlined above
The values of the material input parameters taken into account in the computation are presented as follows: ε = 13.18, m∗ = 0.067m0, I = 400 M W/m2, σs = 1 × 1023 m−3, Tij = 0.14 ps, nr = 3.2, aB = 10.42 nm, Ryd = 5.23 meV

Summary

INTRODUCTION

It is generally accepted that the progress of electronic and opto-electronic devices depends on understanding the basic chemical and physical properties of low-dimensional structures (LDSs) In these LDSs, the geometric confinement limits the movement of charge carriers in space and it displays large changes in electrical and optical properties due to the occurrence of discrete energy distribution. Due to the last developments of semiconductor nanoelectronics, it has become possible to reduce dimensionality from bulk semiconductors to zero-dimensional semiconductor nanostructures (QDs) These nanostructures are very significant because their charge carrier motion is confined in all three directions, and efficient control of the physical properties of these structures becomes possible. It is hoped that this study will allow a lot elaborate specification of the donor states in the nanostructure researched

Electron-impurity Hamiltonian and wave function

Optical absorption coefficients

NUMERICAL RESULTS AND DISCUSSION

CONCLUSIONS