title: Band offset and negative compressibility in graphene-MoS2 heterostructures.
abstract: We use electron transport to characterize monolayer graphene-multilayer MoS2 heterostructures. Our samples show ambipolar characteristics and conductivity saturation on the electron branch that signals the onset of MoS2 conduction band population. Surprisingly, the carrier density in graphene decreases with gate bias once MoS2 is populated, demonstrating negative compressibility in MoS2. We are able to interpret our measurements quantitatively by accounting for disorder and using the random phase approximation (RPA) for the exchange and correlation energies of both Dirac and parabolic-band two-dimensional electron gases. This interpretation allows us to extract the energetic offset between the conduction band edge of MoS2 and the Dirac point of graphene.
authors.affiliation: Microelectronics Research Center, Department of Electrical and Computer Engineering and ‡Department of Physics, The University of Texas at Austin , Austin, Texas 78758, United States.
authors.forename: Stefano
authors.initials: S
authors.lastname: Larentis
authors.forename: John R
authors.initials: JR
authors.lastname: Tolsma
authors.forename: Babak
authors.initials: B
authors.lastname: Fallahazad
authors.forename: David C
authors.initials: DC
authors.lastname: Dillen
authors.forename: Kyounghwan
authors.initials: K
authors.lastname: Kim
authors.forename: Allan H
authors.initials: AH
authors.lastname: MacDonald
authors.forename: Emanuel
authors.initials: E
authors.lastname: Tutuc