Impedance sensors based on silicon-carbon films for detection low concentrations of organic vapors

Abstract

In this research, we reported that manganese and copper atoms were embedded in silicon-carbon films to fabricate impedance organic vapor sensors. Gas sensitive layers were formed using electrochemical deposition of 9:1 CH₃OH/HMDS solutions, followed by thermal annealing at 500 °C for 2 h. Silicon-carbon films contain 4H-SiC, 15R-SiC and 6H-SiC polytypes, as well as amorphous diamond phases. Mott-Schottky plots were used to evaluate the silicon-carbon films conductivity type, flat band potential and carrying density. Sensor operations were examined at ambient temperature and up to 80 % relative humidity to assess their functionality. The silicon-carbon films impedance sensors detected 6–37 ppb toluene vapor. The manganese and copper embedded in silicon-carbon films detected 5–52 ppb isopropanol vapor and remained unchanged in humidity range (40–65 %). However, at humidity level up to 80 %, the sensing response range decreases by ≈1.5–2 times, with isopropanol significantly contributing to the response.