Incoherent Transport through Molecules on Silicon in the vicinity of a Dangling Bond

TL;DR

This paper models how a dangling bond on silicon affects electron transport through a nearby styrene molecule, revealing the importance of electrostatic and electronic effects at different distances.

Contribution

It introduces a theoretical framework that combines electrostatic and electronic contributions to explain incoherent transport near a dangling bond on silicon.

Findings

Good agreement with experiments for molecules far from the DB

Electrostatic effects dominate at larger distances

Electronic contributions become significant within 10 angstroms

Abstract

We theoretically study the effect of a localized unpaired dangling bond (DB) on occupied molecular orbital conduction through a styrene molecule bonded to a n++ H:Si(001)-(2x1) surface. For molecules relatively far from the DB, we find good agreement with the reported experiment using a model that accounts for the electrostatic contribution of the DB, provided we include some dephasing due to low lying phonon modes. However, for molecules within 10 angstrom to the DB, we have to include electronic contribution as well along with higher dephasing to explain the transport features.