Low-Voltage Gas Field Ionization Tunneling Sensor Using Silicon Nanostructures

In this paper, we report the design and characteristics of a field-ionization gas sensor based on freestanding silicon nano structures. Silicon nanostructures fabricated using a three-step chemical/electrochemical technique on silicon wafer were placed between two parallel plates separated by a small gap. The sensor works based on the field ionization tunneling effect. For the first time, it is shown that silicon nanostructures can be used for the purpose. The device was tested for Ar, N2, O2, and He gases in a pressure range of 0.01 <; P <; 10 torr. The device demonstrated a distinctive I - V curve and the ionization voltages for the considered gases. Detected breakdown voltages were much lower than those reported in the literature for gas ionization sensors based on metallic nanowires.