title: Effect of atomic layer deposition temperature on the performance of top-down ZnO nanowire transistors.
abstract: This paper studies the effect of atomic layer deposition (ALD) temperature on the performance of top-down ZnO nanowire transistors. Electrical characteristics are presented for 10-μm ZnO nanowire field-effect transistors (FETs) and for deposition temperatures in the range 120°C to 210°C. Well-behaved transistor output characteristics are obtained for all deposition temperatures. It is shown that the maximum field-effect mobility occurs for an ALD temperature of 190°C. This maximum field-effect mobility corresponds with a maximum Hall effect bulk mobility and with a ZnO film that is stoichiometric. The optimized transistors have a field-effect mobility of 10 cm(2)/V.s, which is approximately ten times higher than can typically be achieved in thin-film amorphous silicon transistors. Furthermore, simulations indicate that the drain current and field-effect mobility extraction are limited by the contact resistance. When the effects of contact resistance are de-embedded, a field-effect mobility of 129 cm(2)/V.s is obtained. This excellent result demonstrates the promise of top-down ZnO nanowire technology for a wide variety of applications such as high-performance thin-film electronics, flexible electronics, and biosensing.
authors.affiliation: School of Electronics and Computer Science, Nano Research Group, University of Southampton SO17 1BJ, Southampton, UK ; Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81110 Skudai, Johor, Malaysia.
authors.forename: Suhana M
authors.initials: SM
authors.lastname: Sultan
authors.affiliation: School of Electronics and Computer Science, Nano Research Group, University of Southampton SO17 1BJ, Southampton, UK.
authors.forename: Nonofo J
authors.initials: NJ
authors.lastname: Ditshego
authors.affiliation: Oxford Instrument Plasma Technology BS49 4AP, Bristol, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Gunn
authors.affiliation: School of Electronics and Computer Science, Nano Research Group, University of Southampton SO17 1BJ, Southampton, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Ashburn
authors.affiliation: School of Electronics and Computer Science, Nano Research Group, University of Southampton SO17 1BJ, Southampton, UK.
authors.forename: Harold Mh
authors.initials: HM
authors.lastname: Chong
keywords: Atomic layer deposition; Field-effect transistor; Top-down fabrication; Zinc oxide nanowire