Quartz Crystal Microbalance Coated with Vanadium Oxide Thin Film for $$\hbox {CO}_{2}$$ CO 2 Gas Sensor at Room Temperature

Abstract

A gas-sensing device based on quartz crystal microbalance (QCM) covered with vanadium oxide thin film has been elaborated to detect $$\hbox {CO}_{2}$$ gas at room temperature. Vanadium oxide thin films were deposited onto QCM substrates by vacuum thermal evaporation technique. The vanadium oxide-coated QCM was heated at $$200\,^{\circ }\hbox {C}$$ for different times. The influence of the annealing time on structural and morphological properties of the deposited films was investigated by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The elaborated QCM/vanadium oxide structures were tested for $$\hbox {CO}_{2}$$ gas sensing. The results show that the sensor sensitivity increases with the annealing time due to the increase in the roughness of the surface. Moreover, the structure heated at $$200\,^{\circ }\hbox {C}$$ for 3 h exhibited a high resonance frequency shift ( $$\Delta f$$ ) under a $$\hbox {CO}_{2}$$ pressure of 40 mbar, fast response time (57 s), short recovery time (43 s), good stability, linearity, reproducibility, and reversibility.