title: Defect Control and n-Doping of Encapsulated Graphene by Helium-Ion-Beam Irradiation.
abstract: We study with Raman spectroscopy the influences of He(+) bombardment and the environment on beam-induced defects in graphene encapsulated in hexagonal boron nitride (h-BN). We show for the first time experimentally the autonomous behavior of the D' defect Raman peak: in contrast to the D defect peak, the D' defect peak is sensitive to the local environment. In particular, it saturates with ion dose in the encapsulated graphene. Electrical measurements reveal n-type conduction in the BN-encapsulated graphene. We conclude that unbound atoms ("interfacials") between the sp(2)-layers of graphene and h-BN promote self-healing of the beam-induced lattice damage and that nitrogen-carbon exchange leads to n-doping of graphene.
authors.affiliation: †Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
authors.forename: Gaurav
authors.initials: G
authors.lastname: Nanda
authors.affiliation: †Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
authors.forename: Srijit
authors.initials: S
authors.lastname: Goswami
authors.affiliation: ‡National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: ‡National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: †Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
authors.forename: Paul F A
authors.initials: PF
authors.lastname: Alkemade
keywords: Helium ion microscopy; graphene; hexagonal boron nitride (h-BN); ion-induced damage; n-doping; self-healing