Optimal distribution of carbon nanotubes in gas sensor design

Breakdown voltage is a unique well-known indicator for gases. Previous work indicate that miniaturized gas ionization sensors, which are made up of two electrodes one of which accommodates vertically aligned carbon nanotubes (CNTs), reduce breakdown voltage thanks to electric field concentration at sharp tips. Modeling of the ionization of the breakdown voltage and optimization of CNTs distribution are reported here. Modeling of CNTs for computational simulations creates a common high aspect-ratio problem due to CNT´s microscale length and nanoscale diameter. This problem is solved by comparison of several models and validation of the most reliable one. Three dimensional modeling with periodic boundary conditions is proven quite suitable for actual span of CNTs on a SiO₂ substrate. Using the model an optimal distribution of CNTs is obtained.