Electrical Contacts and Gas Sensing Analysis of Individual Metal Oxide Nanowires and 3-D Nanocrystal Networks

Abstract

A nanolithography method based on the use of a Dual Beam focused-ion-beam (FIB) equipment to perform electrical contacts on either individual metal oxide nanowires or three-dimensional (3-D) nanocrystal networks is reported. Both advantages and disadvantages of using this nanolithography process compared with other more conventional techniques are discussed. The possibility of using these FIB bottom-up devices in gas sensing application is also presented showing the performances of the gas sensors based on single nanowires and 3D nanocrystal networks of metal oxides. For it, two- and four-probe electrical measurements have been used determining the features associated to the contact resistances. To eliminate any influence of the contact values, AC Impedance Spectroscopy techniques have been adapted on individual nanowires facilitating the analysis of the gas sensing mechanisms in single metal oxide nanocrystal.