Hello,
I want to make STM break junction experiment using Gold. So, my setup is made up by a gold tip and a substrate of Gold/SiO2/Si stack lying on a nanopositioner. The substrate is brought in contact with the tip to form gold atomic contacts that can be monitored using I-V curves. So I have to apply a voltage on the substrate. We do this at room temperature
However, the only way I could come up with was to solder a small wire on the substrate. But this method degrades the substrate as it has to be really pure and clean. Also, we have to use a flame to clean it so it will spread the solder everywhere. I tried with several mechanical ways to contact a wire on the substrate but it is hard to form a good connection. Do you know some ways to create a good contact, that would allows us to easily remove the susbtrate and not contaminate it ?
Hi Jérémie Pirard
I did similar experiments during my degree. Have you tried using something like a gold spring pin (also called a pogo pin) to make the mechanical contact? A non-mechanical option could be to use silver paint/silver DAG (available from Agar Scientific) to copper tape. It's an approach I use all the time for samples for scanning electrochemical microscopy and similar. This should be easier to remove than solder, and easier to make the initial contact to gold with. I'm not sure how it will hold up to flame annealing though, the paint and tape may need to be added after the annealing process.
In very ancient times, to obtain a reliable electrical contact to the substrate, the method of thermal compression was used. But without knowing all the details of the experiment, I can not say whether it is suitable in your case.
I think what you're looking for is called ultrasonic bonding/welding, where a metallic bond is made by vibrational movement, and it can be done with very thin wires without solder.
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