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I What affects resistivity?

  1. Jul 1, 2016 #1
    I am depositing VO2 thin films on quartz and aluminum substrates and I need to find out whether the choice of substrate can effect the resistivity of the VO2 film. I know resistivity is a function of temperature but am not sure if it is effected by substrate choice. Any thoughts?
     
  2. jcsd
  3. Jul 1, 2016 #2
    Knowing that "VO2 has a phase transition very close to room temperature(~66 °C). Electrical resistivity, opacity, etc, can change up several orders.",
    I expect that VO2 properties are strongly pressure and structure dependent. Various substrates will exert strong various levels of chemical pressure on a monocrystalline layer, for which I expect quite a big impact from the substrate. Polycrystalline thin films show an intrinsic metal-semiconductor transition at 68C. Expect surprises.
    What do you want to achieve?
    https://en.wikipedia.org/wiki/Vanadium(IV)_oxide
    http://www.sciencedirect.com/science/article/pii/S0040609013016404
     
    Last edited by a moderator: Jul 1, 2016
  4. Jul 1, 2016 #3
    Well the transition is induced by temperature and I know that resistivity is a function of temperature. However, resistivity is only a material specific property and since what we are depositing is still only VO2 and I am thinking the structure will be the same (no matter if we use quartz or aluminum substrate), I suspect that the resistivity for both films would be the same. So do you think that purely the substrate would effect the resistivity measurements assuming that there will still be a temperature induced insulator to metal transition?
     
  5. Jul 1, 2016 #4

    berkeman

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    Sorry if I'm missing something obvious, but how can you measure the resistivity of the film when it's deposited on a conducting aluminum substrate?
     
  6. Jul 1, 2016 #5
    There is no reason to expect (without prior experimental knowledge) the properties of thin films to be the same as for the bulk material. And the resisitivity depends strongly on crystal structure and the defects in the structure, which both may be influenced by the substrate.

    As an extreme example, diamond and graphite are still only carbon but their resistivities are many order of magnitude apart.
     
  7. Jul 2, 2016 #6

    radium

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    Electronic properties of materials definitely depend on the substrate. For example, graphene on boron nitride apparently has an enhanced mobility and a tunable band gap. Bilayer graphene also has different electronic properties than graphene

    In general resistivity depends on material structure, material defects, and electron electron interactions. In the latter case, an example is the "normal" phase of Cuprates superconductors above the critical temperature near . This state is called a "strange" metal and the resistance is linear in T.
     
  8. Jul 4, 2016 #7
    This all makes sense. Does anyone have any examples from the literature of VO2 grown on quartz and/or aluminum that would give me an idea on their respective resistivity values? I am having a hard time finding some literature on that topic.
     
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