The role of passivants on the stoichiometry of CdSe and GaAs nanocrystals

Abstract

Passivating molecules are introduced during the growth of semiconductor nanocrystals (NCs) to arrest their growth leading to nanoparticles of a desired size. In order to carry out this function, they bind to the surface atoms of the NC, removing any band gap states in the process. While they have been observed to play a role in modifying various other physical properties of materials, in this work we consider examples of two well-known binary semiconductors, GaAs and CdSe, and find within our calculations that the passivating ligands can play an important role in stabilizing highly nonstoichiometric semiconductors. This has important implications in the observed optical and electronic properties of binary semiconductor NCs where usually no suitable passivant exists for the anion.