High Sensitive Room Temperature No2 Gas Sensor Based on the Avalanche Breakdown Induced by Schottky Junction in Tio2-Sn3o4 Nanoheterojunctions

A novel sensor based on Schottky junction inducing avalanche breakdown effect in TiO2-Sn3O4 nanoheterojunctions is assembled. High sensitivity for NO2 gas sensing is demonstrated at room temperature. TiO2-Sn3O4 nanocompositewas synthesized as the gas sensing layer and Schottky contact was formed by Au electrodes. The Schottky contact functions as a “gate” which can trigger the avalanche breakdown effect in the TiO2-Sn3O4 heterojunctions. By tuning the Schottky barrier height through the responsive variation of the surface chemisorbed gas and the bias on the device, NO2 at a concentration from 5 to 50 ppm can be detected with an average response time of 8 s at room temperature. This nanostructured device is a promising candidate for application in high-sensitivity and high-speed NO2 gas sensor. The methodology and working principle illustrated in this paper present a new sensing mechanism that can be readily and extensively applied to other gas sensing systems.