Response of oxygen plasma-treated thick film tin oxide sensor array for LPG, CCl 4, CO and C 3H 7OH

Abstract

In the present paper, studies have been made to analyze the effect of oxygen plasma and dopants on the room temperature sensitivity of tin oxide, thick film gas sensors for various gases. To achieve this, an array of sensors was fabricated by thick film technology using tin oxide paste doped with Pd, Pt, CuO, ZnO, Cd and SnO 2. Subsequently, the fabricated array was annealed in oxygen plasma for 15 min. The response of the array has been studied for different concentrations of CO, LPG, CCl 4 and C 3H 7OH. The response–recovery time analysis of the fabricated array has also been carried out. These studies reveal that the sensitivity of oxygen plasma-treated array is much higher at room temperature compared with the untreated array. Moreover, addition of different dopants enhance the sensitivity and selectivity of the sensor to various gases/odours. The Pt-doped sensor has been found to be more sensitive to CO and LPG, whereas the Pd-doped sensor shows a good response towards CCl 4 and C 3H 7OH, and the Cd-doped sensor was found to show a fairly good response to all four gases.