I am confused whether the ITO coated glass is conductive or not .
The method which i use is - " I put the knob of multi-meter on beep sound and then touch both the electrodes on film if it beeps then i finalized that its conductivity . "
But a number of times when i do the same it does not beeps on the same substrate .
what is the proper method to check the conductivity of substrate (ito coated ).
also in some experiment i put the substrate in furnace , afater taking out from furnace again it was'nt showing any beep .
Can someone help me how to check ?
Dear Yogesh Singh,
You can certainly check which side of an ITO substrate (glass or ITO film sides) is conductive using a multimeter. What I suggest is to use the multimeter readings instead of beep sounds to justify whether conducting or not. The readings should be less than 100 ohm if the two probes are at less than 5mm range. If you want to measure the real value of your ITO conductivity, you need to have a proper set-up of four point probe station. Hope it helps.
Hello Yogesh,
the "beep method" is well suited if you want to examine wired connections. The beep sound switches on if the resistance of the connection exceeds a minimum. So, you need low ohmic contacts. This method is used by electricians to check complex curcuits. For you, this method is unsufficient by following reasons:
- The resistance of thin layers is not low ohmic
- the metal-semiconductor contact (multimeter-wire with ITO) produces Schottky barriers what gives high ohmic contacts.
- the contact is not reproducable due to humidity of air, oxidation of contact ares and contaminations
So I recommend to clean your contacts in organic solutions (spirit, aceton ect.). Better is to fix metallic contacts (indium, or Ga-In-eutectic). Fellows use often In-Ga-solution and fix test wires with it. You can buy this contact liquid per internet.
( https://www.sigmaaldrich.com/catalog/product/aldrich/495425?lang=de®ion=DE )
With Regards
R. Mitdank
thanks Xuhua Wang mam and Rüdiger Mitdank sir , for a highly informative answer . To explain further - MY plan was to coat TiO2 on ito glass for water splitting applications . And a little part of ITO glass was left bare for making contact . THANKS AGAIN
As Xuhua Wang, and Rüdiger Mitdank .
However, some high (Temperature, and/or time) heat treatment (or other functionalization) experiments might create changes in the structural (e.g. and the electrical) properties of ITO (FTO[1]), commonly, amorphous to progressive polycrystalline form, as well as further growth of the grains.
In such (ITO-modification) cases, you need more, or even much more, than the 'good, but limited, 'beep', (and other[2] DC-) tools[3-6].
1. Consider FTO as an alternative to ITO for your high heat treatment cases. https://www.researchgate.net/post/Why_FTO_is_more_thermally_stable_than_ITO
2. Put the knob of your DMM (multi-meter) on Capacitance mode. http://artsites.ucsc.edu/EMS/Music/tech_background/Z/impedance.html
3. Measuring Sheet Resistance, in: Sheet Resistance: A Guide to Theory https://www.ossila.com/pages/sheet-resistance-theory
4. ITO Sheet Resistance Definition and Significance https://www.diamondcoatings.com/ito-sheet-resistance/
5. Functionalization of indium-tin-oxide electrodes by laser-nanostructured gold thin films for biosensing applications https://www.sciencedirect.com/science/article/abs/pii/S0169433215024514
6. Electrical and optical properties of ITO thin films prepared by DC magnetron sputtering for low-emitting coatings https://arxiv.org/pdf/1409.5293.pdf
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