Characterization of nanometer-sized, mechanically exfoliated graphene on the H-passivated Si(100) surface using scanning tunnelling microscopy

TL;DR

This study presents a method for depositing nanometer-sized graphene layers on H-passivated Si(100) surfaces and investigates their electronic properties using STM and tunnelling spectroscopy, revealing size-dependent energy gaps.

Contribution

It introduces a new technique for creating and characterizing nanometer-scale graphene on silicon surfaces, enabling detailed electronic structure analysis.

Findings

Nanometer-sized graphene monolayers and bilayers can be deposited with 2-10 nm dimensions.

Size-dependent energy gaps from 0.1 to 1 eV were observed in small graphene flakes.

Number of graphene layers can be identified from STM topography.

Abstract

We have developed a method for depositing graphene monolayers and bilayers with minimum lateral dimensions of 2-10 nm by the mechanical exfoliation of graphite onto the Si(100)-2x1:H surface. Room temperature, ultra-high vacuum (UHV) tunnelling spectroscopy measurements of nanometer-sized single-layer graphene reveal a size dependent energy gap ranging from 0.1-1 eV. Furthermore, the number of graphene layers can be directly determined from scanning tunnelling microscopy (STM) topographic contours. This atomistic study provides an experimental basis for probing the electronic structure of nanometer-sized graphene which can assist the development of graphene-based nanoelectronics.