An Integrated CO2 Sensor Using TiO2NT/RGO Hybrid Sensing Layer with embedded Micro hot Plate

Abstract

In the present work, the comparison of the hybrid structure (TiO2NT/RGO: TiO2 nanotube (TiO2NT) and Reduced Graphene Oxide (RGO)), along with its pristine counterpart (TiO2NT) based device, related to its fabrication, characterization and oxidizing vapor sensing potentiality integrated with Micro-heater, is reported. On top of the microheater, the deposited sputtered metal is Titanium (Ti) and Platinum (Pt) with the thickness of 10 nm / 80 nm. The calculated Temperature Coefficient of Resistance (TCR) of the sensor is 0.001690 and it’s determined by the measuring of resistance. The temperature of heater is selected in between of $25^{\circ}\mathrm{C}-250^{\circ}\mathrm{C}$. TiO2 nanotubes were fabricated through anodization method and the nanotubes were covered via the RGO layer in an unequal manner. After the detailed study, the vapor sensing performance of the pristine structure along with its hybrid counterpart were tested for the detection of different oxidizing vapor like CO2 and NO. The hybrid sensor showed $\sim$35%, $\sim$58.14%, and $\sim$66.06% response magnitude for 5 ppm, 10 ppm, and 50 ppm of CO2 vapor concentrations, with the optimum temperature of $60^{\circ}\mathrm{\lt p\gt C}$ respectively, whereas for the pristine (the nanotube sensor) structure the nanotube sensor offered the response magnitude of $\sim$21.08%, $\sim$33.25% and $\sim$51.76% respectively, at its optimum temperature of $135^{\circ}\mathrm{C}$. After doing the comprehensive illustration between the pristine structure and the hybrid structure, a detailed discussion has been presented correlating different sensing parameters like response magnitude, response time and recovery time.