Structural and electronic properties of Si/Ge nanoparticles

TL;DR

This theoretical study investigates the stability and electronic properties of various Si/Ge nanoparticles, revealing surface localization of frontier orbitals and electron donation/acceptance tendencies, with implications for optical properties.

Contribution

It provides a comparative analysis of the stability and electronic structure of different Si/Ge nanoparticle configurations, highlighting surface effects and electron transfer behaviors.

Findings

(Si)Ge particles are more stable than (Ge)Si particles.

Surface orbitals influence optical properties significantly.

Ge atoms tend to donate electrons, Si atoms tend to accept electrons.

Abstract

Results of a theoretical study of the electronic properties of (Si)Ge and (Ge)Si core/shell nanoparticles, homogeneous SiGe clusters, and Ge$|$Si clusters with an interphase separating the Si and Ge atoms are presented. In general, (Si)Ge particles are more stable than (Ge)Si ones, and SiGe systems are more stable than Ge$|$Si ones. It is found that the frontier orbitals, that dictate the optical properties, are localized to the surface, meaning that saturating dangling bonds on the surface with ligands may influence the optical properties significantly. In the central parts we identify a weak tendency for the Si atoms to accept electrons, whereas Ge atoms donate electrons.