title: Nitride surface passivation of GaAs nanowires: impact on surface state density.
abstract: Surface nitridation by hydrazine-sulfide solution, which is known to produce surface passivation of GaAs crystals, was applied to GaAs nanowires (NWs). We studied the effect of nitridation on conductivity and microphotoluminescence (μ-PL) of individual GaAs NWs using conductive atomic force microscopy (CAFM) and confocal luminescent microscopy (CLM), respectively. Nitridation is found to produce an essential increase in the NW conductivity and the μ-PL intensity as well evidence of surface passivation. Estimations show that the nitride passivation reduces the surface state density by a factor of 6, which is of the same order as that found for GaAs/AlGaAs nanowires. The effects of the nitride passivation are also stable under atmospheric ambient conditions for six months.
authors.affiliation: Ioffe Institute , Saint-Petersburg 194021, Russia.
authors.forename: Prokhor A
authors.initials: PA
authors.lastname: Alekseev
authors.forename: Mikhail S
authors.initials: MS
authors.lastname: Dunaevskiy
authors.forename: Vladimir P
authors.initials: VP
authors.lastname: Ulin
authors.forename: Tatiana V
authors.initials: TV
authors.lastname: Lvova
authors.forename: Dmitriy O
authors.initials: DO
authors.lastname: Filatov
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Nezhdanov
authors.forename: Aleksander I
authors.initials: AI
authors.lastname: Mashin
authors.forename: Vladimir L
authors.initials: VL
authors.lastname: Berkovits
keywords: GaAs nanowire; nitridation; photoluminescence; surface passivation