Detection Of Nitric Oxide Base On Aligned Carbon Nanotubes Arrays Field-effect Transistor

A high sensitivity and rapid response detection method of the nitric oxide (NO) gas is developed in this thesis. NO gas sensors were based on field effect transistors (FET) using the horizontal aligned single-walled carbon nanotubes arrays (SWCNTs). The SWCNTs were synthesized by chemical vapor deposition on a single crystal quartz substrate using the methane as carbon source. Copper chloride (or ferric chloride ), the catalyst precursor, were dispersed by the polyvinylpyrrolidone and prepared for the regular strips graphics on the quartz substrate. This approach had improved activity of the catalyst and increased density of the carbon nanotube arrays, the average density near to 5 SWCNTs per micrometer. Field Emission Scanning Electron Microscopy, Atomic Force Microscopy and Raman spectrum were applied to characterize the carbon nanotubes' structure respectively. Poly(methyl methacrylate) film using as a mediator carrier was employed to transfer the SWCNTs from the quartz substrate to silicon dioxide / silicon substrate. We utilized microfabrication technologies to manufacture FET devices using the transferred SWCNTs film. Electrical measurement rusults of these FET devices show that the carbon nanotubes were p-type mode and the mobility was at a low level. With the support of the SWCNTFET sensors devices, a study of scope,time and mechanism for the NO molecules response were performed ultimately. The experiments data indicated that these sensors could achieve a high sensitivity and fast real-time response for the NO molecules, the concentration detection limit of NO gas was up to 2 part per billion.