SAW Gas Sensors with Carbon Nanotubes Films

A surface acoustic wave (SAW) gas sensor with multiwalled carbon nanotubes (CNTs) layered films as chemically interactive nanomaterial is presented. A SAW two-port resonator integrated on ST-cut quartz substrate has been functionally characterized as oscillator in dual differential mode at the resonant frequency of 433.92 and 915 MHz. Nanocomposite layers based on filler of CNTs, grown by RF-plasma enhanced chemical vapor deposition, have been prepared by the Langmuir-Blodgett (LB) technique to coat the SAW microdevices for organic vapor detection, at room temperature. Results concerning the SAW sensing performance towards ethanol, methanol, acetone, m-xylene, and toluene are described. These results demonstrate clearly the potential of the SAW CNTs-nanocomposite chemical microsensors at high frequencies for the fabrication of low-cost and highly gas-sensitive devices for promising room-temperature sensing operations.