A hybrid nanostructure array for gas sensing with ultralow field ionization voltage.

We fabricate a unique hybrid nanostructure array for gas sensing based on the polarization mechanism at the nanoscale. It is shown that with platinum nanocrystallites on the top of each nanoneedle, this array can work at ultralow voltages (less than 10 V) as a field ionization gas sensor. We believe that the polarized platinum brings about a local enhanced electrical field, leading to the direct field ionization of gas molecules, which is confirmed by calculations of the charge accumulation and electrical field distribution.