Does substrate choice impact resistivity in VO2 thin films?

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Discussion Overview

The discussion centers on whether the choice of substrate, specifically quartz versus aluminum, affects the resistivity of VO2 thin films. Participants explore the relationship between substrate properties and the electrical characteristics of the films, considering factors such as temperature-induced phase transitions and structural influences.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that resistivity is a function of temperature and questions if substrate choice impacts resistivity, given that VO2 is being deposited on different substrates.
  • Another participant suggests that the properties of VO2 are strongly dependent on the substrate due to chemical pressure effects, indicating that different substrates could significantly influence resistivity.
  • A participant argues that resistivity is a material-specific property and posits that the resistivity of VO2 films on quartz and aluminum would be the same, assuming the structure remains unchanged.
  • Concerns are raised about measuring resistivity on a conducting aluminum substrate, questioning the validity of such measurements.
  • One participant emphasizes that thin film properties may differ from bulk material properties, citing that crystal structure and defects influenced by the substrate can affect resistivity.
  • Another participant provides examples from other materials, indicating that electronic properties can vary significantly based on substrate interactions, such as graphene on boron nitride.
  • A request for literature examples of VO2 grown on quartz and aluminum is made, highlighting a need for empirical data on their respective resistivity values.

Areas of Agreement / Disagreement

Participants express differing views on the impact of substrate choice on the resistivity of VO2 thin films. While some argue that substrate influences are significant, others maintain that resistivity should remain consistent across substrates if the material structure is similar. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants acknowledge that the resistivity of thin films may not directly correlate with bulk material properties, and there are concerns regarding the measurement techniques on conducting substrates. The discussion also highlights the complexity of factors influencing resistivity, including crystal structure and defects.

Who May Find This Useful

Researchers and practitioners in materials science, particularly those focused on thin film deposition and electronic properties of materials, may find this discussion relevant.

hornboy95
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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?
 
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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
 
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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?
 
hornboy95 said:
I am depositing VO2 thin films on quartz and aluminum substrates
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?
 
hornboy95 said:
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.
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.
 
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.
 
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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