back to probe station

A semiconducting nanotube will have a resistance between 100k-ohms and 1M-ohm. The probe contact can be as high as 1M-ohm, so be careful to make sure the resistance you are measuring is the nanotube and not probe contact resistance.

Once you know the probes are dirty, move them away from your sample and clean them with acetone. Kimwipes, wet with acetone, can be used like sandpaper to clean the tip.

The minimum resistance for the probe station is about 5k-ohms. You get this resistance when touching the two needle probes together, or if you have made good contact to a circuit of low resistance. You can use this to see if your probes are making good contact by touching two areas which you know make a short and check the resistance. Making good contact seems to be fairly fickle. Two probes that are clearly touching the metal contacts may have poor conductivity, but may greatly increase in conductivity when bumped or shifted slightly.