Gas sensors based on Paschen's law using carbon nanotubes as electron emitters

In the case of typical gas sensors responding by gas adsorption on the surface, it is very difficult to detect inert gases which have low chemical adsorption energies under normal conditions. Carbon nanotubes (CNTs) are well known as electron emitters in applications like field emission displays. In this work, we fabricate a physical gas sensor (or vacuum sensor) using CNTs with compactness and reliability of the fabrication process and discuss current–voltage characteristics as a function of the vacuum pressure. The proposed sensor, based on an electrical discharge theory known as Paschen's law, works by figuring changes of the discharge current depending on the concentration of gases which can ionize through collisions with electrons emitted from CNT emitters.