Surface nano-patterning through styrene adsorption on Si(100)

TL;DR

This study uses ab initio methods to explore how styrene molecules adsorb on Si(100) surfaces, revealing mechanisms for controlled nano-patterning through covalent bonding and phenyl interactions.

Contribution

It provides new insights into the adsorption process and how coverage influences surface electronic properties and pattern formation.

Findings

Vinyl group forms covalent Si-C bonds via [2+2] cycloaddition.

Coverage affects the surface bandgap and electronic patterning.

Phenyl-phenyl interactions create regular electronic wire patterns.

Abstract

We present an ab initio study of the structural and electronic properties of styrene molecules adsorbed on the dimerized Si(100) surface at different coverages, ranging from the single-molecule to the full monolayer. The adsorption mechanism primarily involves the vinyl group via a [2+2] cycloaddition process that leads to the formation of covalent Si-C bonds and a local surface derelaxation, while it leaves the phenyl group almost unperturbed. The investigation of the functionalized surface as a function of the coverage (e.g. 0.5 -- 1 ML) and of the substrate reconstruction reveals two major effects. The first results from Si dimer-vinyl interaction and concerns the controlled variation of the energy bandgap of the interface. The second is associated to phenyl-phenyl interactions, which gives rise to a regular pattern of electronic wires at surface, stemming from the pi-pi coupling. These findings suggest a rationale for tailoring the surface nano-patterning of the surface, in a controlled way.