PIEZORESISTIVE MICROCANTILEVERS 3D-PATTERNED USING ZNO-NANORODS@SILICON-NANOPILLARS FOR ROOM-TEMPERATURE ETHANOL DETECTION

This paper reports a self-actuating and self-sensing gravimetric ethanol sensor, based on 3D ZnO-Nanorods@Si-Nanopillars (ZnO-NRs@Si-NPLs) as the sensing material which, for the first time, are selectively fabricated on a piezoresistive silicon microcantilever (MC, Fig. 1). This novel ZnO-NRs@Si-NPLs functionalized microcantilever (MC) was found to be highly sensitive to ethanol detection at room-temperature, with a sensitivity of hundred times higher than that of a ZnO-nanofilm-covered MC. Furthermore, fast response and recovery time of few seconds to low-concentration ethanol can be expected. In addition, real-time sensing is possible using a low-cost, low-weight, miniaturized phase-locked-loop (PLL) based system, indicating the potential of our proposed sensor for future portable gas-sensing in practical applications.