Device Modeling of Double Layered TiO2 Nanotube Array Based Resistive Vapor Sensor

Abstract

Single and double layered TiO 2 nanotube array were synthesized by anodic oxidation method. Anodization voltage was varied to develop double layered TiO 2 nanotube array. Developed materials were characterized structurally and morphologically by X-ray diffraction spectroscopy (XRD)and field emission scanning electron microscopy (FESEM)respectively. Sandwich structure devices with Au top electrode and Ti bottom electrode were fabricated by using both single and double layered TiO 2 nanotubes for vapor sensing application. A simplified device modeling was introduced to establish the sensing mechanism of both the TiO 2 nanotube arrays. Additional interlayer junctions in double layered TiO 2 nanotubes array, enhanced the vapor sensing performance significantly. Double layered TiO 2 nanotubes array was able to show 92.4% of response magnitude for ethanol concentration of 160 ppm at 300 K where 55.2% response was observed for mono-layered TiO 2 nanotube array.