Investigation of degassing Method for CNTs Thin Film gas Sensors

Abstract

It is well known that Carbon Nanotube conductance has high sensitivity to NH3 and NO2 gases. Although the CNT sensors showed short sensing response time and exponential increase or decrease of conductance with trapping gas molecules at the CNT surfaces, the recovery time due to degassing needs to be reduced for commercial gas sensor applications. Absorbed gas molecules require activation energy to desorb from the CNT surfaces. Conventionally, we have applied heat treatment or UV treatment to supply the required activation energy. Here, we have investigated degassing characteristics at the CNT surfaces depending on applied AC electric field strength and frequency. Inter digitated electrode pattern were fabricated and placed under the SWCNT thin film sensor. AC electric fields were applied to the pattern, from 5Vpp and between 10KHz and 10MHz frequency. We compared the AC electric field recovery characteristic to that of the heat aided degassing.