Effects of shape and composition on the properties of CdS nanocrystals

Abstract

Using first-principles electronic structure calculations, we studied the relative stability between hexagonal wurtzite (WZ) and cubic zinc-blende (ZB) structures and the electronic properties of the CdS nanocrystals of varying shape and surface composition. Our study shows substantial enhancement of the stability of the WZ phase over that of the ZB phase upon moving from a spherical to a cylindrical shape. Our study provides microscopic understanding of the dominant stability of the WZ phase in cylindrically shaped nanocrystals. The calculated band gaps also show interesting variation as a function of varying shape and surface composition.