How can I create an ohmic contact with selenium?

I would like to be able to measure the electrical resistance of selenium past its melting point, but to do this I need to create an Ohmic contact between the selenium and my multi-meter. What metals or other materials would work best?

• Should it really matter if you use four-point method? – user137289 Mar 11 '17 at 22:15

1 Answer

If you are just trying to achieve a momentary, temporary contact to measure conductivity, the meter's supplied probes should be fine. Since $Se$ is a a photovoltaic and photoconductive semiconductor you may get different results in your measurements depending on the probe polarity (current direction), and what frequency and intensity of light your sample is exposed to.

In the molten state $Se$ will combine with certain metals as referenced here to create metallic selenides, so it's probably best to avoid the more common materials used for electrodes and use platinum or tungsten since the selenides can act to increase resistance over the pure selenium metal.