Effect of quantum dot shape of the GaAs/AlAs heterostructure on interlevel hole light absorption

Boichuk Boichuk,Bilynskyi Bilynskyi,Shakleina Shakleina,Sokolnyk Sokolnyk

doi:10.5488/cmp.16.33702

Abstract

The effect of quantum dot shape on the hole energy spectrum and optical properties caused by the interlevel charge transition based on the 4x4 Hamiltonian has been studied for the GaAs quantum dot in the AlAs semiconductor matrix. Calculations have been carried out in perturbation theory taking into account the hybridization of states for cubic, ellipsoidal, cylindrical and tetrahedral shapes by changing the volume of a quantum dot. Based on the energy calculations and on the determined wave functions of the hole states we have defined the selection rules and the dependence of the interlevel hole absorption coefficient on QD shapes and volumes.

Highlights

Quantum dots (QDs) have attracted the attention of researchers both as an object of the study of nanoheterostructure physical properties and as an opportunity for different applications of QDs in everyday life.As concerns the practical use, QDs are used in solar batteries, where the shape and size of CdSe/TiO2 QDs make it possible to improve the photoresponse [1], and for the comparison with organic dyes as fluorescent labels based on luminescence and fluorescence [2].Nowadays, various fields of science use the achievements of physics of nanosize heterostructures, quantum dots in particular
Applying the envelope-function approximation to the description of hole states in QDs embedded in a semiconductor matrix, we can find the energy spectrum and wave functions of particles, and examine the optical effects caused by interlevel hole transitions [12, 13]
The aim of the present work is to study the effect of QD shape on the hole energy spectrum and on the optical parameters of a semiconductor nanoheterosystem

Summary

Introduction

Quantum dots (QDs) have attracted the attention of researchers both as an object of the study of nanoheterostructure physical properties and as an opportunity for different applications of QDs in everyday life. The authors of [5] proved that the shape of a quantum dot affects the energy of charges in QDs, and their electronic density of states. Applying the envelope-function approximation to the description of hole states in QDs embedded in a semiconductor matrix, we can find the energy spectrum and wave functions of particles, and examine the optical effects caused by interlevel hole transitions [12, 13]. The aim of the present work is to study the effect of QD shape on the hole energy spectrum and on the optical parameters (the hole transition probability, transition oscillator strength, interband light absorption coefficient) of a semiconductor nanoheterosystem. The calculations have been carried out for the GaAs QD which is placed into the AlAs matrix

The energy and wave functions of bound states of holes in a QD

The interlevel absorption coefficient

Findings

Conclusions