A Room Temperature ZnO-NPs/MEMS Ammonia Gas Sensor

Ting-Jen Hsueh; Ruei-Yan Ding

doi:10.3390/nano12193287

A Room Temperature ZnO-NPs/MEMS Ammonia Gas Sensor

Nanomaterials (Basel). 2022 Sep 21;12(19):3287. doi: 10.3390/nano12193287.

Authors

Ting-Jen Hsueh¹, Ruei-Yan Ding¹

Affiliation

¹ Department of Electronic Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 807, Taiwan.

Abstract

This study uses ultrasonic grinding to grind ZnO powder to 10−20-nanometer nanoparticles (NPs), and these are integrated with a MEMS structure to form a ZnO-NPs/MEMS gas sensor. Measuring 1 ppm NH3 gas and operating at room temperature, the sensor response for the ZnO-NPs/MEMS gas sensor is around 39.7%, but the origin-ZnO powder/MEMS gas sensor is fairly unresponsive. For seven consecutive cycles, the ZnO-NPs/MEMS gas sensor has an average sensor response of about 40% and an inaccuracy of <±2%. In the selectivity of the gas, the ZnO-NPs/MEMS gas sensor has a higher response to NH3 than to CO, CO2, H2, or SO2 gases because ZnO nanoparticles have a greater surface area and more surface defects, so they adsorb more oxygen molecules and water molecules. These react with NH3 gas to increase the sensor response.

Keywords: ZnO; gas sensor; nanoparticles.

Grants and funding

This research was funded by NSTC of Taiwan grant number 110-2221-E-992-047, 111-2221-E-992-029-MY3, 111-2218-E-992-001-MBK, 111-2218-E-006-011-MBK.