Sensitivity Performance of Single Wall Carbon Nanotubes Gas Sensor on Silicon and Porous Silicon

Abstract

Pure single walled carbon nanotubes (pure-SWCNTs) and Functionalized single walled nanotubes (F-SSWCNTs) have been utilized to the manufactured nitrogen dioxide gas sensor. CNTs films have been deposited on (n-type) silicon and porous silicon substrate by drop casting method. A porous silicon layer (PS) was prepared via electrochemical etching. The applied current density was 20 mA / cm2, and the typical electrochemical-etching time was chosen to be about 20 minutes. Upon exposure to fixed test gas mixing ratio (air: gas) NO2 at different operating temperatures, the sensitivity response results show that Pure single walled carbon nanotubes and Functionalized single walled nanotubes deposited on porous silicon have better performances than that deposited on silicon. At RT the F-SWCNTs/Ps sensitivity reaches to 36%, the response and recovery time is about 11 s and 26 s, whereas for SWCNTs/Ps the sensitivity 13.5%, the response and recovery time is about 13 s and 24 s.