title: Enhanced electrical properties and field emission characteristics of AZO/ZnO-nanowire core-shell structures.
abstract: The electrical properties and field-emission characteristics of ZnO nanowires (ZnO-NWs) fabricated using a vapor-liquid-solid method were systematically investigated. In particular, we explored the effects of Al-doped ZnO (AZO) films (thickness 4-100 nm) deposited on ZnO-NWs using an atomic layer deposition (ALD) method on the optoelectronic properties. The results show that the sheet resistance of net-like ZnO-NW structures can be significantly improved, specifically to become ∼1/1000 of the sheet resistance of the as-grown ZnO-NWs, attaining less than 10 Ω Sq(-1). The emission current density measured at the maximum field was roughly quadrupled relative to that of the as-grown ZnO-NWs. The data of the enhanced field-emission characteristics show that, with the ALD system, the AZO films of small resistance are readily coated on a structure with a high aspect ratio and the coating radius is controlled relative to the turn-on voltage and current density. The ultrathin AZO film from a one-monolayer coating process also significantly improved emission properties through modification of the effective work function at the AZO/ZnO-NW surface.
authors.affiliation: Program for Science and Technology of Accelerator Light Source, National Chiao Tung University, Hsinchu 300, Taiwan.
authors.forename: Jheng-Ming
authors.initials: JM
authors.lastname: Huang
authors.affiliation: Program for Science and Technology of Accelerator Light Source, National Chiao Tung University, Hsinchu 300, Taiwan.
authors.forename: Shang-You
authors.initials: SY
authors.lastname: Tsai
authors.affiliation: National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan. csku@nsrrc.org.tw hylee@nsrrc.org.tw.
authors.forename: Ching-Shun
authors.initials: CS
authors.lastname: Ku
authors.affiliation: Department of Applied Science, National Hsinchu University of Education, Hsinchu 30014, Taiwan. cmlin@mail.nhcue.edu.tw.
authors.forename: Chih-Ming
authors.initials: CM
authors.lastname: Lin
authors.affiliation: Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan.
authors.forename: San-Yuan
authors.initials: SY
authors.lastname: Chen
authors.affiliation: National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan. csku@nsrrc.org.tw hylee@nsrrc.org.tw and Department of Applied Science, National Hsinchu University of Education, Hsinchu 30014, Taiwan. cmlin@mail.nhcue.edu.tw.
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Lee