Detection of volatile organic compounds based on low-energy electron scattering according to difference in collisional cross-section

Various types of sensors have been studied to detect volatile organic compounds (VOCs). Here, we developed a sensor that operates with a novel mechanism to achieve detection of VOCs. The tight gap between two facing sets of suspended in-plane nanofibers on top of silicon microelectrodes, as well as the sharp protrusion of nanofibers, allows the generation of a relatively high and non-uniform electric field. This produces leakage of electrons at low applied voltage, resulting in collisions with gas molecules. At that time, the difference in the total cross-section of the gas affects the scattering angle and energy loss of the electrons, and thus the amount of current changes between the two electrodes. VOCs have a relatively large total cross-section at low electron energy compared with other gases, such as nitrogen, hydrogen, and carbon dioxide, such that the measured current decreases. This proposed mechanism extends the approaches applicable to discriminate gaseous species, and the sensor may be an alternative for VOC monitoring systems.