Getting through the nature of silicene: sp2-sp3 two-dimensional silicon nanosheet

TL;DR

This paper investigates the structure and electronic properties of a novel sp2-sp3 hybrid silicon nanosheet on Ag(111), combining experimental Raman spectroscopy and ab-initio calculations to reveal its semiconducting and semimetallic behaviors.

Contribution

It introduces a new crystalline form of silicon nanosheets with mixed sp2-sp3 hybridization characterized by combined experimental and theoretical methods.

Findings

Identified a graphene-like vibrational mode in silicon nanosheets.

Discovered that highly distorted structures are semiconductors.

Low distorted structures exhibit semimetallic properties.

Abstract

By combining experimental techniques with ab-initio density functional theory calculations, we describe the Si/Ag(111) two-dimensional system in terms of a sp2-sp3 crystalline form of silicon characterized by a vertically distorted honeycomb lattice. We show that 2D sp2-sp3 Si NSs are qualified by a prevailing Raman peak which can be assigned to a graphene-like E2g vibrational mode and that highly distorted superstructures are semiconductive whereas low distorted ones behave as semimetals.