A new fluid-based transistor that controls the flow of aqueous ions has been constructed out of a silicon nanotube. Peidong Yang and his colleagues from the University of California, Berkeley, used potassium chloride solution in a 15 μm-long nanotube as the equivalent of a channel in a field-effect transistor, with an external gold electrode playing the role of a gate.
The ability to control the flow of tiny numbers of charged molecules instead of the usual flow of electrons could form the basis for a novel set of devices, running from computing elements through to sensitive chemical sensors.
Further reading
Rong Fan et. al. 2005 Phys. Rev. Lett. 95 086607.