Self-Heating of Top-Down Manufactured ITO Sensors for Accurately Monitoring ppb-Level O 3

Wafer-scale fabrication of high-performance metal oxide semiconductor (MOS) gas sensors, with good reproductivity/uniformity, is essential for their batch deployments as either selective sensors or smart electronic noses, but it remains a big challenge. In this work, we propose a top-down approach for manufacturing O 3 sensors from commercial indium tin oxide (ITO) glasses, which mainly involves laser patterning (etching) and Ar/H 2 plasma treatment. Increased surface roughness induced by Ar/H 2 plasma treatment (60 min) and localized heating (180 °C) via self-heating enable an exceptional O 3 sensing performance, including a drastically improved O 3 response, good selectivity, weak humidity interference and long-term stability. The present ITO sensor enables real-time precise monitoring of ambient O 3 from background-level ∼25 to 200 ppb, verified by the UV photometric ozone analyzer. Moreover, wafer-scale fabrication of sensor arrays with uniform O 3 sensing performance has been demonstrated, raising the hope of smart O 3 sensors for ambient ppb-level O 3 monitoring.