催化剂颗粒对自持放电型碳纳米管气体传感器电极的影响

Study of Catalyst Grains Effect on Electrode of Self-sustaining Discharge Carbon Nanotubes Gas Sensor Array

根据高电场作用下 ,气体的自持暗放电曲线不同区分气体的方法灵敏度高 ,不易产生交叉敏感 ,但是工作电压高。用催化热解法在硅基上生长出垂直于基底的碳纳米管阵列 ,利用碳纳米管的尖端效应 ,使得高电场集中在一个微小的区域内 (纳米级 ) ,从而使得气体导电所需的工作电压大幅度下降。催化热解法生长出的碳纳米管顶端含有催化剂颗粒 ,当其紧密排列时 ,形成屏蔽层 ,减弱了碳纳米管的表面场强。这里 ,提出三步纯化法 ,去除了碳纳米管阵列顶端的催化剂颗粒 ,极大地增强了碳纳米管的表面场强。

The method, which recognize the species and concentration of mixed gases by its selfsustaining 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 on the top of CNTs is removed by using three step purified method in this paper, the electric field intensity is enhanced.