Electrical characterization of buckled graphene films derived from plasma etched silicon carbide.

摘要

Graphene is a 2D allotrope of carbon with exceptional electronic properties and numerous applications. Research in the Surface and Materials Studies Laboratory at West Virginia University has led to the development of a low temperature, halogen based plasma etching process that produces buckled graphene films on 6H-SiC. Films ranging from one to five layers in thickness have been produced. This growth process is scalable with the SiC wafer diameter, and in principle, it resolves many of the difficult issues associated with the manufacturability of large area epitaxial graphene films. The growth process and functionalization of these buckled graphene films have been studied by other in this laboratory. The research described in this dissertation represents the first measurements of the electrical properties of these films. Specifically, current-voltage measurements have been performed to determine the carrier density and conductivity. In addition, Schottky barrier heights and contact resistances for Ti and Ti/Au contacts were determined. Key parameters in these analyses were the number of graphene layers and the annealing temperature which alters the doping level. For single layer films, carrier densities ranging from 2 x 1010 cm-2 to 2 x 1011 cm-2 measured, while conductivities of on the order of 6.8 x 105 Scm-1 were measured. These values compare favorably with normal (flat) graphene. Changes in conductivity resulting from diazonium functionalization of the buckled graphene surface were also studied. The results of these electrical characterization studies demonstrate the significant potential for using buckled graphene films in a variety of molecular electronics applications.