Fabrication of gas ionization sensor based on titanium oxide nanotube arrays

Gas sensors have been fabricated based on field ionization from titanium oxide nanotubes grown on titanium foil. Ordered nanaotube arrays of titanium oxides were grown by the anodization method. We measured breakdown voltages and discharge currents of the device for various gases. Our gas ionization sensors (GIS) presented good sensitivity, selectivity, and short response time. The GISs based on TiO₂ nanotube arrays showed lower breakdown voltage, higher discharge current, and good selectivity. An excellent response observed for Ar compared to other gases. Besides, by introducing 2 % CO and 4 % H₂ to N₂ flow gas, the amount of breakdown voltage shifts about 20 and 70 volts to the lower values, respectively. The GIS works at room temperature and has the ability of detect inert gases with high stability and good linearity. Besides, short response time of about 1 second for the GISs based on TiO₂ nanotube arrays makes them excellent for gas sensing applications. Sharp edges of the nanotubes, through enhancing the applied electric field, reduce operating voltage to the reasonable values and power consumption.