Effect of Shell Thickness on Electron and Hole Transmission Probabilities of a ZnSe/ZnS Core- Shell Quantum Dot

Bashir Mohi Ud Din Bhat,Khurshed A Shah

doi:10.1590/1980-5373-mr-2018-0083

Bashir Mohi Ud Din Bhat, Khurshed A Shah

Open Access

https://doi.org/10.1590/1980-5373-mr-2018-0083

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Journal: Materials Research	Publication Date: Aug 30, 2018
Citations: 4	License type: cc-by

Affiliation: Cluster University Srinagar

Abstract

In this paper we report the effect of shell thickness on transmission probabilities of electrons and holes in the strained configuration of zinc-selenide/zinc-sulphide (ZnSe/ZnS) core-shell quantum dot. The transmission probabilities of electrons/holes were calculated within the frame work of effective mass approximation and quantum mechanical tunneling. In the first attempt, we introduced extra deposit shell thickness of ZnS in the range 0-5nm and calculated its size effects on the transmission of carriers from core to the shell. We observed that quantum dot of small size core show superb characteristics of possible transmissions and the transmission probability of the carriers across the potential barrier can be controlled by varying the shell thickness, which has practical significance for electron transport in quantum dots, electron transfer in bio-sensors and chemo-sensors etc. Moreover, it is also found that for higher values of electron/hole energies (greater than 0.7eV), the transmission probability oscillates, which too has practical significance for quantum oscillators.The study is important from both basic and applied point of view.

Highlights

Recent advanced nanofabrication technology have made it possible to prepare three dimensionally confined quantum dot (QD)[1] and core-shell quantum dot (CSQD) structures whose characteristic dimensions are comparable with the exciton Bohr radius[2,3,4]
The superficial bonds on the surfaces of quantum dots can be coated with suitable organic materials or inorganic materials and the materials used for coating must possess desired band gap and lattice matching so as to give the quantum dot (QD) a structural continuity
The deposited layer is referred to as shell and the quantum dot as a whole is referred to as CSQDs

Summary

1.Introduction

Recent advanced nanofabrication technology have made it possible to prepare three dimensionally confined quantum dot (QD)[1] and core-shell quantum dot (CSQD) structures whose characteristic dimensions are comparable with the exciton Bohr radius[2,3,4]. These structures exhibit optoelectronic properties due to the quantum mechanical nature of the electrons[5,6]. By over coating the ZnSe core by higher band gap ZnS shell results in an enhancement in localization of the charge carriers which has a wide application in calculating spin.

Theoretical Formulations

Results and Discussions

4.Conclusions