title: Creating a Stable Oxide at the Surface of Black Phosphorus.
abstract: The stability of the surface of in situ cleaved black phosphorus crystals upon exposure to atmosphere is investigated with synchrotron-based photoelectron spectroscopy. After 2 days atmosphere exposure a stable subnanometer layer of primarily P2O5 forms at the surface. The work function increases by 0.1 eV from 3.9 eV for as-cleaved black phosphorus to 4.0 eV after formation of the 0.4 nm thick oxide, with phosphorus core levels shifting by <0.1 eV. The results indicate minimal charge transfer, suggesting that the oxide layer is suitable for passivation or as an interface layer for further dielectric deposition.
authors.affiliation: ‡School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: M T
authors.initials: MT
authors.lastname: Edmonds
authors.affiliation: §Australian Synchrotron, 700 Blackburn Road, Clayton, Victoria 3183, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Tadich
authors.forename: A
authors.initials: A
authors.lastname: Carvalho
authors.affiliation: #Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States.
authors.forename: A
authors.initials: A
authors.lastname: Ziletti
authors.affiliation: □Department of Imaging and Applied Physics, Curtin University, Bentley, Western Australia 6102, Australia.
authors.forename: K M
authors.initials: KM
authors.lastname: O'Donnell
authors.forename: S P
authors.initials: SP
authors.lastname: Koenig
authors.affiliation: #Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States.
authors.forename: D F
authors.initials: DF
authors.lastname: Coker
authors.forename: B
authors.initials: B
authors.lastname: Özyilmaz
authors.affiliation: ○Department of Physics, Boston University, Boston, Massachusetts 02215, United States.
authors.forename: A H Castro
authors.initials: AH
authors.lastname: Neto
authors.affiliation: ‡School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia.|△Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 207424111, United States.
authors.forename: M S
authors.initials: MS
authors.lastname: Fuhrer
keywords: XPS; air stability; black phosphorus; oxidation