(235f) Nanofabricated Chemical Sensors Using Aerosol Jet Printing Method

One-dimensional (1-D) nanostructures including semiconducting single-walled carbon nanotubes (SWNTs) have been demonstrated as good candidates for ultra-sensitive chemical sensors because of the high surface-to-volume ratio of nanostructures and their unique electronic conductance. However, the assembly of SWNTs across the microfabricated electrodes to form miniaturized sensors is always challenging and time-consuming with current methods, including guided CVD growth, polar molecular patterning, atomic force microscopy (AFM) manipulation, etc. The recent developments in printed electronics are expected to find an alternating way to fabricate cheap sensors by precisely printing well dispersed nanostructures on substrates. Among the printing techniques, the aerosol jet printing is one of the most promising techniques for making large area, inexpensive nanoelectronic components. It is a room temperature operated, and non-contact process which can be used to deposit a wide variety of materials onto a wide variety of substrates.

In this research, we demonstrate a cost effective, high-throughput and manufacturable printing method to fast fabricate semiconducting SWNTs based chemical sensors. Using aerosol jet printing method, Percolating networks of semiconducting SWNTs inks can be printed onto rigid or flexible substrates. The electrical properties of sensors were characterized with Field Effect Transistor (FET) configuration. The thin film transistors made by printing have demonstrated low operating voltage, good reliability and the printing process can be performed in air, in contrast to current organic thin-film transistors which have to be made in glove box in a controlled environment. Preliminary sensing results of printed flexible nanoelectronic sensors showed good sensitivity and fast response time to NH₃ and NO₂ at room temperature operation. The printing technology allows quick design and fabrication of electronic circuits, avoiding conventional semiconductor fabrication processes, which is a promising step toward the batch manufacturing of miniaturized sensor devices with low cost and extensive analytical capabilities.­­­­­­­­­­­­­­­­­­