Development of a Ferrite Film Based Solid State Sensor System for Ultra Low Concentration Hydrogen Sulfide Gas Detection
Ravindra Kumar Jha, Aman Nanda, Ranajit Sai, Kaushal Kishore, Anshul Yadav, R. D. Ralandinliu Kahmei, Navakanta Bhat
Abstract
We report on a selective hydrogen sulfide gas sensor based on zinc ferrite film which is obtained by a microwave-assisted solvothermal deposition route. The response of the chemiresistive device is found to be in the range of 1872% - 90% for 5.6 ppm – 0.3 ppm of H<sub>2</sub>S gas at an operating temperature of 250°C. The density functional theory studies suggest physisorption of the H<sub>2</sub>S molecules at the partially-inverted ZnFe<sub>2</sub>O<sub>4</sub> surface as the reason behind the fast rise (of the order of ~40 sec) and fall time (of the order of ~70 sec) with complete recovery of the device. Finally, a dual-differential subtractor based auto-balancing interface circuit is proposed to drive this sensor which is advantageous in terms of accuracy and particularly suitable for a device such as ours, which has a wide dynamic range.