Fabrication of ozone gas sensor based on FeOOH/single walled carbon nanotube-modified field effect transistor

Abstract

A novel ozone (O3) sensor is fabricated using commercial metal oxide field effect transistor (MOSFET), modified with single-walled carbon nanotubes (SWCNTs). In this study, integrated circuit (IC: BS250) was selected as the selective probe for O3 detection. For this purpose, a plastic cover on the surface of the drain was drilled to bare the drain surface, followed by its modification with nitrogen and sulfur-functionalized SWCNTs by chemical vapor deposition (CVD) process. The CVD-synthesized SWCNTs were then electrodeposited with FeOOH nanostructures. According to the figures of merit, the fabricated sensor gave a linear output from 20 to 450 parts per billion (ppb). Detection limit was also 4.1 ppb. Relative standard deviation (RSD) for seven replicate analyses was 3.61%. Based on 90% of maximum response (t90), the response time was ∼1.5 min. Calibration sensitivity was measured to 1.3 mV/ppb. No interference was observed, when introducing at least 500 folds of interferences of gaseous species such as H2O, HCl, H2S, O2, H2, CO, CO2, NO2, SO2, Cl2, C2H2, CH4 and volatile organic compounds (VOCs) to 250 ppb of O3 solution. Reliability of the sensor was also evaluated via determination of O3 in different air samples.