Role of contacts in graphene transistors: A scanning photocurrent study

被引：323

作者：

Mueller, T. ^{[1
]}

Xia, F. ^{[1
]}

Freitag, M. ^{[1
]}

Tsang, J. ^{[1
]}

Avouris, Ph. ^{[1
]}

机构：

[1] IBM Corp, Thomas J Watson Res Ctr, Yorktown Hts, NY 10598 USA

来源：

PHYSICAL REVIEW B | 2009年 / 79卷 / 24期

基金：

奥地利科学基金会;

关键词：

electronic structure; graphene; multilayers; nanotube devices; optical microscopy; photoconductivity; CARBON NANOTUBE TRANSISTORS; DEVICES; BARRIERS;

D O I：

10.1103/PhysRevB.79.245430

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

A near-field scanning optical microscope is used to locally induce photocurrent in a graphene transistor with high spatial resolution. By analyzing the spatially resolved photoresponse, we find that in the n-type conduction regime a p-n-p structure forms along the graphene device due to the doping of the graphene by the metal contacts. The modification of the electronic structure is not limited only underneath the metal electrodes but extends 0.2-0.3 mu m into the graphene channel. The asymmetric conduction behavior of electrons and holes that is commonly observed in graphene transistors is discussed in light of the potential profiles obtained from this photocurrent-imaging approach. Furthermore, we show that photocurrent imaging can be used to probe single-layer/multilayer graphene interfaces.

引用

页数：6

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