title: Seeding atomic layer deposition of alumina on graphene with yttria.
abstract: Integrating graphene into nanoelectronic device structure requires interfacing graphene with high-κ dielectric materials. However, the dewetting and thermal instability of dielectric layers on top of graphene makes fabricating a pinhole-free, uniform, and conformal graphene/dielectric interface challenging. Here, we demonstrate that an ultrathin layer of high-κ dielectric material Y2O3 acts as an effective seeding layer for atomic layer deposition of Al2O3 on graphene. Whereas identical Al2O3 depositions lead to discontinuous film on bare graphene, the Y2O3 seeding layer yields uniform and conformal films. The morphology of the Al2O3 film is characterized by atomic force microscopy and transmission electron microscopy. C-1s X-ray photoemission spectroscopy indicates that the underlying graphene remains intact following Y2O3 seed and Al2O3 deposition. Finally, photoemission measurements of the graphene/SiO2/Si, Y2O3/graphene/SiO2, and Al2O3/Y2O3/graphene/SiO2 interfaces indicate n-type doping of graphene with different doping levels due to charge transfer at the interfaces.
authors.affiliation: Department of Physics, University of South Florida , Tampa, Florida 33620, United States.
authors.forename: Arjun
authors.initials: A
authors.lastname: Dahal
authors.forename: Rafik
authors.initials: R
authors.lastname: Addou
authors.forename: Angelica
authors.initials: A
authors.lastname: Azcatl
authors.forename: Horacio
authors.initials: H
authors.lastname: Coy-Diaz
authors.forename: Ning
authors.initials: N
authors.lastname: Lu
authors.forename: Xin
authors.initials: X
authors.lastname: Peng
authors.forename: Francis
authors.initials: F
authors.lastname: de Dios
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Kim
authors.forename: Moon J
authors.initials: MJ
authors.lastname: Kim
authors.forename: Robert M
authors.initials: RM
authors.lastname: Wallace
authors.forename: Matthias
authors.initials: M
authors.lastname: Batzill
keywords: Al2O3; X-ray photoemission spectroscopy; Y2O3; dielectric; doping; graphene; seed layer