Microscopically-Tuned Band Structure of Epitaxial Graphene through Interface and Stacking Variations Using Si Substrate Microfabrication

Hirokazu Fukidome,Toyohiko Kinoshita,Takuo Ohkochi,Masato Kotsugi,Takayuki Ide,Masaharu Oshima,Yusuke Kawai,Maki Suemitsu,Naoka Nagamura,Koji Horiba,Hiroshi Kumighashira,Toshihiro Shinohara

doi:10.1038/srep05173

Abstract

Graphene exhibits unusual electronic properties, caused by a linear band structure near the Dirac point. This band structure is determined by the stacking sequence in graphene multilayers. Here we present a novel method of microscopically controlling the band structure. This is achieved by epitaxy of graphene on 3C-SiC(111) and 3C-SiC(100) thin films grown on a 3D microfabricated Si(100) substrate (3D-GOS (graphene on silicon)) by anisotropic etching, which produces Si(111) microfacets as well as major Si(100) microterraces. We show that tuning of the interface between the graphene and the 3C-SiC microfacets enables microscopic control of stacking and ultimately of the band structure of 3D-GOS, which is typified by the selective emergence of semiconducting and metallic behaviours on the (111) and (100) portions, respectively. The use of 3D-GOS is thus effective in microscopically unlocking various potentials of graphene depending on the application target, such as electronic or photonic devices.

Highlights

Graphene exhibits unusual electronic properties, caused by a linear band structure near the Dirac point
We demonstrate the microscopic tuning of the band structure of epitaxial graphene on a 3D microfabricated Si substrate (3D-graphene on Si (GOS)) through stacking with the aid of microelectromechanical system (MEMS) technology, anisotropic wet etching which produces (111) and (100) microfacets on a Si(100) substrate
The etching by the tetramethyl ammonium hydroxide (TMAH) aqueous solution is used to expose Si(111) microfacets on Si(100) substrates, which are frequently used as the standard fabrication procedure for MEMS devices[29]

Summary

Introduction

Graphene exhibits unusual electronic properties, caused by a linear band structure near the Dirac point. This band structure is determined by the stacking sequence in graphene multilayers. We present a novel method of microscopically controlling the band structure This is achieved by epitaxy of graphene on 3C-SiC(111) and 3C-SiC(100) thin films grown on a 3D microfabricated Si(100) substrate (3D-GOS (graphene on silicon)) by anisotropic etching, which produces Si(111) microfacets as well as major Si(100) microterraces. Epitaxial growth of graphene on SiC bulk crystals produces large-scale, high-quality graphene on SiC substrates, which are already in use for power device applications[13,14]. GOS is becoming a promising graphene production method, based on its advantages, such as the cost of the wafer and compatibility with existing Si-based device technologies

Methods

Results

Conclusion