title: Sputtering Deposition of Sandwich-Structured V2O5/Metal (V, W)/V2O5 Multilayers for the Preparation of High-Performance Thermally Sensitive VO2 Thin Films with Selectivity of VO2 (B) and VO2 (M) Polymorph.
abstract: For specific application to an uncooled infrared detector, VO2 thin films should have a series of characteristics including purposefully chosen polymorphs, accurate stoichiometry, phase stabilization, a high temperature-coefficient of resistance (TCR), and suitable square-resistance. This work reports controllable preparation of high-performance VO2 films via post annealing of a sandwich-structured V2O5/metal (V, W)/V2O5 multilayer precursor, which was deposited by RF magnetron sputtering. This sandwich structure can dynamically regulate oxygen contents and doping element levels in the films, enabling us to achieve accurate regulation of stoichiometry and polymorphs. The precursor films undergo a B to M phase transition depending on the quantity of the metal layers. At the thickness of the metal layer below a limitation, the resulting film after heat treatment was VO2 (B), and above the limitation, the product was VO2 (M). The optical modulation of the VO2 (M) in the near-infrared region can be tuned from 1.2 to 39.8% (ΔT2000 nm). TCR values can range from -1.89 to -4.29%/K and the square-resistances at room temperature (R0) from 69.68 to 12.63 kΩ. The simplicity in phase regulation of the present method and the superior optical and electrical properties of the films may allow its wide applications in thermo-opto-electro sensing devices.
authors.affiliation: School of Materials Science and Engineering, Shanghai University , Shanghai 200444, China.
authors.forename: Hengwu
authors.initials: H
authors.lastname: Liu
authors.affiliation: School of Materials Science and Engineering, Shanghai University , Shanghai 200444, China.
authors.forename: Dongyun
authors.initials: D
authors.lastname: Wan
authors.affiliation: National Center for Physics, Quaid-I-Azam University , Islamabad 44000, Pakistan.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Ishaq
authors.affiliation: School of Materials Science and Engineering, Shanghai University , Shanghai 200444, China.
authors.forename: Lanli
authors.initials: L
authors.lastname: Chen
authors.affiliation: School of Materials Science and Engineering, Shanghai University , Shanghai 200444, China.
authors.forename: Beibei
authors.initials: B
authors.lastname: Guo
authors.affiliation: School of Materials Science and Engineering, Shanghai University , Shanghai 200444, China.|Materials Genome Institute, Shanghai University , Shanghai 200444, China.
authors.forename: Siqi
authors.initials: S
authors.lastname: Shi
authors.affiliation: School of Materials Science and Engineering, Shanghai University , Shanghai 200444, China.|Materials Genome Institute, Shanghai University , Shanghai 200444, China.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Luo
authors.affiliation: School of Materials Science and Engineering, Shanghai University , Shanghai 200444, China.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Gao
keywords: phase regulation; sandwich structure; thin film; uncooled infrared detector; vanadium dioxide (VO2)