Synthesis and optical properties of Type I CdSe/ZnSe core–shell quantum dot

Abstract

We have synthesized thiol-capped CdSe/ZnSe core–shell quantum dot nanostructures at low temperature; have characterized them by steady-state absorption and photoluminescence (PL) studies. Band-gap energy alignment for CdSe and ZnSe semiconductor materials suggested that they can form Type-I core–shell quantum dot. Our steady state absorption and emission studies confirmed the formation of Type-I core–shell band alignment between CdSe and ZnSe quantum dots. On excitation of CdSe quantum dot only surface states emission was observed, however on ZnSe shell formation we could also observed band-edge emission of CdSe. Time-resolved emission studies have also been carried out in CdSe core and CdSe/ZnSe core–shell QD materials. Band-edge emission which appeared due to shell formation for CdSe found to decay faster as compared to surface state emission of CdSe QD and CdSe-ZnSe core–shell.