Novel Carbon Nanotube-Based Nanostructures for High-Temperature Gas Sensing

In this early stage of research, most carbon nanotubes (CNTs) are grown as random and entangled strings on substrates, which are of little interest to engineers. Recently, successful growth of vertically aligned multi-wall nanotubes (MWNTs) through the anodized aluminum oxide (AAO) nano-porous template has attracted the engineers' interests. This is because both the diameter and the length of nanotubes are controllable by using the template and the AI203 template also provides a perfect insulating material for isolation of conductive nanotubes from each other. Most of the above successful experiments were carried out on aluminum substrates, Very recently, we successfully grew vertically aligned MWNTs on silicon substrates through the AAO template. To the best of our knowledge, there are no attempts to utilize the vertically aligned CNTs from AAO templates for fabrication of chemical gas sensors, Our vertically aligned CNTs can be used to fabricate highly robust gas sensors with potential for high temperature applications, In this proposal, we plan to use our vertically aligned CNTs as a platform for fabrication, characterization and optimum design of chemical gas sensors for high temperature applications. We aim to pursue research in three main thrusts. In the first thrust, building upon our success, we continue to study the growth mechanisms of MWNTs using the flame synthesis technique and to improve the quality of the nanotubes for particular use for chemical gas sensors in high temperature. The nanotube-based sensing structure will be modified through the nanotemplate modification. In the second thrust, we aim to utilize the modified vertically aligned CNTs for fabrication of robust capacitive sensors. In the third thrust, we will pursue theoretical modeling and numerical simulation of nanostructures and gas sensors, including diffusion of gas molecules and electrical properties of CNTs upon exposure to gas molecules. The proposed research is to advance the CNT-based gas sensors toward high performance and high-temperature applications through nanostructure modification and modeling. The PI's and Co-Pl's experience and existing strength will ensure that the project be carried out fully as proposed. The proposed work will also impact high school students in Eastern and Southern Kentucky communities (economically depressed groups associated with the coal mining industry).