A Room Temperature ZnO-NPs/MEMS Ammonia Gas Sensor

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.

Recent advancements in physical and chemical MEMS sensors

“…11C). 94 Gas sensors to detect various gases driven by a similar principle have been frequently reported. 95–98 Simultaneous detection with a single sensor of multiple gases (H 2 and CO 2 ) has also been achieved using the sensitivity difference of gases.…”

The effect of UV light irradiation on the gas-sensing properties of the quartz crystal microbalance sensor combined with ZnO film

“…We detected the ammonia vapor in a mediumhumidity environment, hence oxygen ions react with ammonia on the surface of the ZnO thin lms and water ions participate in the reaction [44]. The reactions between oxygen ions and ammonia could be written as [40,44]:…”

Ppb-Level Hydrogen Sulfide Gas Sensor Based on the Nanocomposite of MoS2 Octahedron/ZnO-Zn2SnO4 Nanoparticles

“…Several gas sensors based on SMOs such as zinc oxide (ZnO), zinc gallate (ZnGa 2 O 4 ), tin oxide (SnO 2 ), nickel cobaltite (NiCo 2 O 4 ), zinc stannate (Zn 2 SnO 4 ), copper oxide (CuO), etc., possess some good properties such as precision, low cost, small dimensions, long-term stability and environmental friendliness; because of these properties, SMOs could be considered the primary candidates for the detection of toxic gases as well in photo-catalysis, etc. [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Plenty of research has shown that some complex metal oxides have been widely used as gas sensors in the last decades.…”