Study of catalyst grains effect on electrode of self-sustaining discharge carbon nanotubes gas sensor array

The method, which recognize the species and concentration of mixed gases by its self-sustaining discharge I-V curve under the high electric field intensity, is provided with good stability and selectivity. However, the discharge voltage is very high. The carbon nanotubes (CNTs) array is deposited on silicon substrate vertically using the pyrogenation method. The high electric voltage is reduced in great number by focusing the large electric field intensity on nano-region with the help of the point effect of CNTs. However, the tops of CNTs have catalyst grains, which formed shielded layer that reduce the electric field intensity. The catalyst grains is removed by using three steps purifying method in this paper, the electric field intensity is enhanced.