The effects of strain and spacer layer in CdSe/CdS/ZnS. and CdSe/ZnS/CdS core/glen quantum dots


Pisheh H. S. , Gheshlaghi N., Ünlü H.

PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, vol.85, pp.334-339, 2017 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 85
  • Publication Date: 2017
  • Doi Number: 10.1016/j.physe.2016.07.007
  • Title of Journal : PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
  • Page Numbers: pp.334-339

Abstract

The effects of lattice mismatch induced interface strain on the structural, optical and dielectric properties of CdSe based Cd(Zn)S shell and Cd(Zn)S/Zn(Cd)S multishell quantum dots (QDs) is studied. Introducing Zn(Cd) S spacer layer to the CdSe/Cd(Zn)S core/shell structure is found to influence induced interfacial strain through changing the lattice parameter, band gap and band offset of core/shell nanostructure. Lattice parameter of spacer layer affected by outer shell, changes the interface strain in the core region. Theoretically obtained strain in the core/shell(multishell) is used in the effective mass approximation (EMA) to determine the capped core diameter. We show that introducing ZnS spacer layer to the CdSe/CdS core/shell QDs rises the amount of strain and cause more decrease in the core size in CdSe/ZnS/CdS. Furthermore, CdS sandwiched between CdSe/ZnS decreases the amount of strain in crystal and suppresses the size decrease of the core in the CdSe/ZnS. Good agreement is found between the strain included EMA core size predictions in core/shell and multishell and observed size image from transmission electron microscopy (TEM) measurements of bare CdSe core nanocrystals.