Fabrication of single-nanowire sensing devices by electron beam lithography

In this paper, we report on the feasibility of single nanowire devices fabrication by electron beam lithography. SnO2 and ZnO nanowires bundles have been synthesized by vapor-liquid-solid technique, dispersed in isopropanol and then deposited on SiO2/Si substrates. Once the nanowire has been selected, the electrodes have been patterned on the photoresist by the electron beam. Finally, after Pt sputtering and subsequent lift-off, we have obtained samples with SnO2 or ZnO nanowire and Pt electrodes deposited on it. The electrical characteristics of the devices have been preliminary investigated by DC measurements and impedance spectroscopy. The SnO2 single nanowire devices show a good sensitivity to relative humidity. The ZnO single nanowire device shows three orders of magnitude increase of the current when exposed to UV light and a fast recovery of the baseline in air when the UV light is switched off.