Strain-sensitive size modulations in ZnSe/ZnS quantum dots grown on GaAs substrates

Abstract

Strain effects on sizes and emission energies of ZnSe/ZnS quantum dots (QDs) have been investigated. The initial strain in the ZnSe QD layer was altered by adjusting the thickness of the ZnS buffer. Consistent blueshifts of the ground-state emission from 4 monolayer ZnSe QDs were observed with increasing the thickness of the ZnS buffer from 20 to 40 nm. Atomic-force microscopy revealed that the blueshifts are due to a continuous QD size reduction. We estimated the emission energy as a function of the initial strain in the ZnSe QD layer, which shows that the band-gap engineering is possible through the strain modification. (C) 2004 American Institute of Physics.