An Efficient Microsensor System for Selective Detection of Methanol Using TiO2 Nanotubes

Abstract

11This work is supported by Visvesvaraya Young Scientist Fellowship and CENSe Lab, IISc BangaloreAn integrated micro-heater based $\mathrm{TiO}_{2}$ nanotube (NT) device is reported in this paper. Detailed micro-fabrication technique, structural and morphological characterization and sensing performance of the device to different alcohol vapors (e.g. Methanol, Ethanol and 2-Propanol) have been reported. The integrated Ti-Pt based micro-heater (fabricated by DC magnetron sputtering) was used to control the temperature of the sensing material $(\mathrm{TiO}_{2}\text{NT}]$ for the detection of different test vapors. The Temperature Coefficient of Resistance (TCR) of the sensor was determined by varying the heater temperature (27-200 °C). 500 nm oxide layer was used for the heater insulation thickness. On top of the insulated micro-heater, 100 nm of Ti thin film was sputtered. $\mathrm{TiO}_{2}$ nanotubes were prepared by electrochemical anodization method. After detailed characterization, the sensor showed $\sim 23.79\%, \sim 31.02\%, \sim 49.97\%, \sim 71.32\% \text{and} \sim 80.39\%$ response magnitude in the range of 10–400 ppm of Methanol concentration, at optimized temperature 130 °C. Selectivity study revealed relatively better Methanol sensing performance, compared to that of Ethanol and 2-Propanol.