Chemiresistive Sensor Array Based on Semiconducting Metal Oxides for Environmental Monitoring

Abstract

We present gas sensing performance based on 2Χ2 sensor array with four different elements (TiO2, SnO2, WO3 and In2O3 thin films) fabricated by rf sputter. Each thin film was deposited onto the selected SiO2/Si substrate with Pt interdigitated electrodes (IDEs) of 5m spacing which were fabricated on a SiO2/Si substrate using photolithography and dry etching. For 5 ppm NO2 and 50 ppm CO, each thin film sensor has a different response to offers the distinguishable response pattern for different gas molecules. Compared with the conventional micro-fabrication technology, 2Χ2 sensor array with such remarkable response pattern will be open a new foundation for monolithic integration of high-performance chemoresistive sensors with simplicity in fabrication, low cost, high reliablity, and multifunctional smart sensors for environmental monitoring.