We make devices out of semiconductor nanowires which are filamentary crystals that grow like a forest on flat substrates. One challenge that we face is to cut down the forest, isolate a single nanowire and build it into a multilayer structure of a transistor-like device. For years we used to rely on a ‘random’ method: grab thousands of wires and spread them on a chip where we wish to fabricate a transistor. But now we have this neat setup:
It is an optical microscope just powerful enough to barely make out a single nanowire. Next to it is a micromanipulator featuring three grey knobs for moving in X-Y and Z. In this setup we are able to break off a single nanowire from the forest, carry it over to another chip and place it in a desired location.
Here is an example where my student picked up a couple of nanowires (this sometimes can happen) and dropped them in between markers that will help us find back the location later. The idea of this setup came to me from Aachen, where students in the group of Prof. Morgenstern showed me a similar setup. I am greatful to them, as it makes our life much easier. They have published a very nice paper reviewing this instrument.