title: Microstructural analysis and transport properties of MoO and MoC nanostructures prepared by focused electron beam-induced deposition.
abstract: By electron-beam-induced deposition, we have succeeded in the direct fabrication of nanowires of molybdenum oxide (MoOx) and molybdenum carbide (MoC) on a SiO2 substrate set in a scanning electron microscope. In order to prepare MoOx specimens of high purity, a precursor gas of molybdenum hexacarbonyl [Mo(CO)6] is used, mixed with oxygen gas. On the other hand, MoC is grown by mixing H2O gas with the precursor gas. The electrical transport properties of the nanowires are investigated by the DC four-terminal method. A highly resistive MoOx nanowire prepared from an as-deposited specimen by annealing in air shows nonlinear current-voltage characteristics and a high photoconductivity. The resistivity ρ of an as-deposited amorphous MoC (a-MoC) nanowire takes its maximum at a temperature T ≈ 10 K and decreases to ≈ 0 with decreasing temperature. This behavior of ρ(T) indicates the possible occurrence of superconductivity in a-MoC nanowires. The characteristic of ρ(T) below the superconducting transition temperature Tc ≈ 4 K can be well explained by the quantum phase-slip model with a coherence length ξ(0) ≈ 8 nm at T = 0.
authors.affiliation: Advanced ICT Research Institute, National Institute of Information and Communications Technology, 588-2 Iwaoka, Kobe, Hyogo 651-2492, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Makise
authors.affiliation: Surface Physics and Structure Unit, National Institute for Materials Science, 3-13 Sakura, Tsukuba 305-0003, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Mitsuishi
authors.affiliation: Department of Materials Science and Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Shimojo
authors.affiliation: Department of Physics, Kyushu University, 6-10-1 Hakozaki, Higashiku, Fukuoka 812-8581, Japan.
authors.forename: Bunju
authors.initials: B
authors.lastname: Shinozaki