title: p-Type ZnO nanowire arrays.
abstract: Well-aligned ZnO nanowire (NW) arrays with durable and reproducible p-type conductivity were synthesized on alpha-sapphire substrates by using N2O as a dopant source via vapor-liquid-solid growth. The nitrogen-doped ZnO NWs are single-crystalline and grown predominantly along the [110] direction, in contrast to the [001] direction of undoped ZnO NWs. Electrical transport measurements reveal that the nondoped ZnO NWs exhibit n-type conductivity, whereas the nitrogen-doped ZnO NWs show compensated highly resistive n-type and finally p-type conductivity upon increasing N2O ratio in the reaction atmosphere. The electrical properties of p-type ZnO NWs are stable and reproducible with a hole concentration of (1-2) x 10(18) cm(-3) and a field-effect mobility of 10-17 cm2 V(-2) s(-1). Surface adsorptions have a significant effect on the transport properties of NWs. Temperature-dependent PL spectra of N-doped ZnO NWs show acceptor-bound-exciton emission, which corroborates the p-type conductivity. The realization of p-type ZnO NWs with durable and controlled transport properties is important for fabrication of nanoscale electronic and optoelectronic devices.
authors.affiliation: Centre Of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong SAR, People's Republic of China.
authors.forename: G D
authors.initials: GD
authors.lastname: Yuan
authors.forename: W J
authors.initials: WJ
authors.lastname: Zhang
authors.forename: J S
authors.initials: JS
authors.lastname: Jie
authors.forename: X
authors.initials: X
authors.lastname: Fan
authors.forename: J A
authors.initials: JA
authors.lastname: Zapien
authors.forename: Y H
authors.initials: YH
authors.lastname: Leung
authors.forename: L B
authors.initials: LB
authors.lastname: Luo
authors.forename: P F
authors.initials: PF
authors.lastname: Wang
authors.forename: C S
authors.initials: CS
authors.lastname: Lee
authors.forename: S T
authors.initials: ST
authors.lastname: Lee