A general electrodeposition-based method for in situ construction of resistive-type semiconductor film gas-sensor with excellent sensing performance

Abstract

For the construction of a resistive-type gas-sensor, it is usually required for a sensing film to be fabricated on a non-conductive substrate. The in situ construction of a sensor by subjecting the substrate to an electrodeposition method is impossible and there have been no related reports on this. Herein, taking the in situ construction of a SnO₂ film sensor as an example, a novel electrodeposition-based method was introduced. A conductive graphite coating was firstly fabricated on the non-conductive substrate for the implementation of the electrodeposition, and then a calcining process was employed. The conductive pristine graphite coating was found to become non-conductive after being calcined for more than 70 min at 500 °C, resulting in the final electrodeposited film being able to work as a sensing film. Some important parameters related to the sensing performances, including the formation, the conductivity, the electrodeposition time, the calcining time and the working temperature, were systematically studied. Under the optimal conditions, the SnO₂ film sensor exhibited high sensitivity, a fast response and recovery, and long-term stability in the detection of ethanol gas with concentrations ranging between 1–100 ppm. The electrodeposition-based method is reproducible, mass-productive and general. It is therefore practical and promising for the construction of various semiconductor film sensors.