title: Identification of a strong contamination source for graphene in vacuum systems.
abstract: To minimize parasitic doping effects caused by uncontrolled material adsorption, graphene is often investigated under vacuum. Here we report an entirely unexpected phenomenon occurring in vacuum systems, namely strong n-doping of graphene due to chemical species generated by common ion high-vacuum gauges. The effect-reversible upon exposing graphene to air-is significant, as doping rates can largely exceed 10(12) cm(-2) h(-1), depending on pressure and the relative position of the gauge and the graphene device. It is important to be aware of this phenomenon, as its basic manifestation can be mistakenly interpreted as vacuum-induced desorption of p-dopants.
authors.affiliation: DPMC-MaNEP, Université de Genève, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland. GAP, Université de Genève, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Caillier
authors.forename: Dong-Keun
authors.initials: DK
authors.lastname: Ki
authors.forename: Yuliya
authors.initials: Y
authors.lastname: Lisunova
authors.forename: Iaroslav
authors.initials: I
authors.lastname: Gaponenko
authors.forename: Patrycja
authors.initials: P
authors.lastname: Paruch
authors.forename: Alberto F
authors.initials: AF
authors.lastname: Morpurgo