A Single Microcantilever-Type Gas Sensor with Enhanced Sensitivity to Ethanol by Sputtering ZnO with Au Embedded in O2 Atmosphere

This paper proposes a microcantilever-type zinc oxide (ZnO) gas sensor fabricated using typical micro-electro-mechanical system (MEMS) process. To achieve low power consumption, we developed a long narrow single cantilever beam and the sensing region is at the free end of it. ZnO was sputtered under the atmosphere of O2 as the sensing layer. And a thin Au buried layer was deposited to form the “sandwiched” structure of a thin Au layer between two ZnO layers. Ethanol, as a typical volatile gas, was chosen to verify the performance of the proposed sensor. The results indicate that the “sandwiched” sensing layer shows higher response to ethanol compared with single-layer ZnO, and the best sensitivity to 100 ppm ethanol is 7.11. Besides, the response time is 12 s and the sensor consumes a low power consumption of only 5.81 mW.