High Temperature and High Sensitive NO_x Gas Sensor with Hetero-Junction Structure using Laser Ablation Method

Abstract

In order to develop a high temperature (200°C∼400°C) and high sensitive NO_x gas sensor, we developed a new structure of SiC-based hetero-junction device Pt/SnO₂/SiC/Ni, Pt/In₂O₃/SiC/Ni and Pt/WO₃/SiC/Ni using a laser ablation method for the preparation of both metal (Pt) electrode and metal-oxide film. It was found that Pt/In₂O₃/SiC/Ni sensor shows higher sensitivity to NO₂ gas compared with the Pt/SnO₂/SiC/Ni and Pt/WO₃/SiC/Ni sensor, whereas the Pt/WO₃/SiC/Ni sensor had better sensitivity to NO gas. These results suggest that selective detection of NO and NO₂ gases may be obtained by choosing different metal oxide films.