Abstract: “We have demonstrated vertically aligned, multi-walled carbon nanotube (MWCNTs) based alcohol sensor with good selectivity and sensitivity up to 50 ppth (ppth=parts per thousand). Vertically aligned CNTs were synthesized onto silicon substrates using chemical vapor deposition (CVD) system. The sensor was exposed to different alcohols and the impedance was measured using HIOKI LCR Hi tester – 3522-50 system. The results indicates that the sensor is capable of sensing different types of alcohols in various concentration ranges. It exhibits fast, reversible, selective response for different alcohol samples. We have tested the response of the sensor with alcohol concentrations from 50ppth to 100ppth. The impedance of bare sensor was 2.9896 MΏ which was changed to 12.7 MΏ for isopropanol, 33.8 MΏ for butanol, and 48.2 MΏ for ethanol. The sensor can easily reset to its original value by applying small amount of heat using micro-heater fabricated on a PCB board for this application. Based on o”

Keywords: Sensor, Carbon nanotubes, Impedance Spectroscopy.