title: Exceptional charge transport properties of graphene on germanium.
abstract: The excellent charge transport properties of graphene suggest a wide range of application in analog electronics. While most practical devices will require that graphene be bonded to a substrate, such bonding generally degrades these transport properties. In contrast, when graphene is transferred to Ge(001) its conductivity is extremely high and the charge carrier mobility derived from the relevant transport measurements is, under some circumstances, higher than that of freestanding, edge-supported graphene. We measure a mobility of ∼ 5 × 10(5) cm(2) V(-1) s(-1) at 20 K, and ∼ 10(3) cm(2) V(-1) s(-1) at 300 K. These values are close to the theoretical limit for doped graphene. Carrier densities in the graphene are as high as 10(14) cm(-2) at 300 K.
authors.affiliation: University of Wisconsin-Madison , Madison, Wisconsin 53706, United States .
authors.forename: Francesca
authors.initials: F
authors.lastname: Cavallo
authors.forename: Richard
authors.initials: R
authors.lastname: Rojas Delgado
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Kelly
authors.forename: José R
authors.initials: JR
authors.lastname: Sánchez Pérez
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Schroeder
authors.forename: Huili Grace
authors.initials: HG
authors.lastname: Xing
authors.forename: Mark A
authors.initials: MA
authors.lastname: Eriksson
authors.forename: Max G
authors.initials: MG
authors.lastname: Lagally
keywords: Germanium substrate; doping; graphene; high mobility; interface states; low sheet resistivity