Understanding Asymmetric Transportation Behavior in Graphene Field-Effect Transistors Using Scanning Kelvin Probe Microscopy

Author

Liu, W.J. ; Yu, H.Y. ; Xu, S.H. ; Zhang, Q. ; Zou, X. ; Wang, J.L. ; Pey, K.L. ; Wei, J. ; Zhu, H.L. ; Li, M.-F.

Author_Institution

Sch. of Electr. & Electron. Eng., Nanyang Technol. Univ., Singapore, Singapore

Volume

32

Issue

2

fYear

2011

Firstpage

128

Lastpage

130

Abstract

Scanning Kelvin probe microscopy (SKPM) is applied to experimentally understand the asymmetric behaviors in hole and electron transportation regions in graphene field-effect transistors (FETs). With gate modulation, the transition from p-p-p to p-n-p (for a Ag or Pd source/drain junction with graphene) or from n-p-n to n-n-n (for an Al source/drain junction with graphene) is verified by SKPM, which is believed to be responsible for the asymmetric transport. The odd resistance (R_odd) is positive for Ag (or Pd)/single-layer-graphene (SLG) FETs with ΔWF_intrinsic >; 0, while R_odd is negative for Al/SLG devices with ΔWF_intrinsic <; 0, where ΔWF_intrinsic is defined as the work function difference between metal and intrinsic graphene.

Keywords

field effect transistors; graphene; nanoelectronics; scanning probe microscopy; silver; C-Ag; FET; SKPM; SLG; asymmetric transportation behavior; electron transportation region; gate modulation; graphene field-effect transistor; odd resistance; scanning Kelvin probe microscopy; single-layer-graphene; Asymmetric transport; field-effect transistors (FETs); graphene; scanning Kelvin probe microscopy (SKPM);

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2010.2093500

Filename

5672574