AVS 58th Annual International Symposium and Exhibition
    Graphene and Related Materials Focus Topic Friday Sessions
       Session GR+MS+EM-FrM

Paper GR+MS+EM-FrM6
Rectification at Graphene / Semiconductor Junctions: Applications Beyond Silicon Based Devices

Friday, November 4, 2011, 10:00 am, Room 208

Session: Graphene Device Physics and Applications
Presenter: Sefaattin Tongay, University of Florida
Authors: S. Tongay, University of Florida
X. Miao, University of Florida
K. Berke, University of Florida
M. Lemaitre, University of Florida
B.R. Appleton, University of Florida
A.F. Hebard, University of Florida
Correspondent: Click to Email
Schottky barriers are crucial and necessary device components of metal-semiconductor field effect transistors (MESFETs) and high electron mobility transistors (HEMTs). Here, we report on the formation of Schottky barriers at graphene-multilayer graphene/semiconductor junction interfaces which have been characterized by current density vs. voltage (J-V) and capacitance vs. voltage (C-V) measurements. After graphene transfer onto various semiconductors such as Si, GaAs, GaN and SiC, we observe a strong rectification at the interface, i.e., high (low) resistance in the reverse (forward) bias directions. The J-V characteristics have been analyzed using thermionic emission theory and the extracted barrier height values are consistent with the Schottky-Mott model. When capacitance is plotted as 1/C2 vs V, a linear dependence is observed, which by extrapolation to the intercept identifies a built in potential that is consistent with the Schottky barrier height extracted from J-V measurements. Graphene's low Fermi energy together with its robust thermal, chemical, structural and physical properties provide numerous advantages when used to form Schottky barriers in device applications: namely, voltage tunability of the Schottky barrier height, stability to high temperatures, resistance to impurity diffusion across the interface, and the use of absorbates to chemically tune the Fermi energy and hence the Schottky barrier height.