Nanocrystaline ZnO-Si heterojunction methane sensor

ZnO gas sensors are widely used for environmental monitoring and industrial applications due to their advantages like small dimensions, low cost and convenient operation. On interaction with reducing gases, adsorbed oxygen concentration results in change of conductivity. The change in conductivity defines a measure of gas concentration. As the gas sensing mechanism is a surface reaction, use of nanostructured material improves gas sensing characteristics. Thus ZnO is greatly recognized for different commercial applications. In the present work a sol-gel derived Si-ZnO hetero junction with Au and AI gate pad is fabricated for the purpose of methane sensing. The characteristics of the device are studied by varying the temperature from 50°C to 250°C. The optimum temperature and voltage are calculated through the V-I characteristics with the presence of the reducing gas. The response magnitude of the device is found as -52%.