title: Covalent functionalization and passivation of exfoliated black phosphorus via aryl diazonium chemistry.
abstract: Functionalization of atomically thin nanomaterials enables the tailoring of their chemical, optical and electronic properties. Exfoliated black phosphorus (BP)-a layered two-dimensional semiconductor-exhibits favourable charge-carrier mobility, tunable bandgap and highly anisotropic properties, but it is chemically reactive and degrades rapidly in ambient conditions. Here we show that covalent aryl diazonium functionalization suppresses the chemical degradation of exfoliated BP even after three weeks of ambient exposure. This chemical modification scheme spontaneously forms phosphorus-carbon bonds, has a reaction rate sensitive to the aryl diazonium substituent and alters the electronic properties of exfoliated BP, ultimately yielding a strong, tunable p-type doping that simultaneously improves the field-effect transistor mobility and on/off current ratio. This chemical functionalization pathway controllably modifies the properties of exfoliated BP, and thus improves its prospects for nanoelectronic applications.
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Ryder
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Wood
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Spencer A
authors.initials: SA
authors.lastname: Wells
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Deep
authors.initials: D
authors.lastname: Jariwala
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.|Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Tobin J
authors.initials: TJ
authors.lastname: Marks
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: George C
authors.initials: GC
authors.lastname: Schatz
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.|Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Hersam