Does Moisture Influence the Chemical Detection of Gas Molecules Adsorbed on Single-Wall Carbon Nanotubes?

In this work, the role of water in the detection of hydrazine (N$_{2}$H$_{4})$ by a single-wall carbon nanotube (SWCNT) is investigated using first principles electronic structure calculations (DFT/GGA--USPP)[1]. This calculation is undertaken to interpret the experimental resistivity measurements for N$_{2}$H$_{4}$ adsorbed on SWCNT that reveal an $n$-type behavior [2]. Our preliminary theoretical studies of the adsorption of N$_{2}$H$_{4}$ on SWCNT revealed physisorption for N$_{2}$H$_{4}$ and an unaltered band structure for the SWCNT [3]. This prompted us to look into the role of water on the bonding of N$_{2}$H$_{4}$ to the SWCNT. We found that, by introducing a monolayer of water film on the (8,0) SWCNT, the adsorption of N$_{2}$H$_{4}$ can introduce occupied states near the Fermi level, exhibiting an $n$-type behavior. However, the introduction of just few water molecules was not sufficient to influence the electronic structure of N$_{2}$H$_{4}$/SWCNT. Presently, we are studying the influence of water films on the chemical detection of a variety of other gas molecules (N$_{2}$, NH$_{3, }$\textit{etc}.) by SWCNTs, and the results from such studies will also be reported. [1]. G. Kresse \textit{et al}. Phys. Rev. B \textbf{54}, 11169 (1996). [2]. S. Desai, \textit{et al}. (APS, March 2008). [3]. M. Yu, \textit{et al}. (APS, March 2008).