Zinc Oxide (ZnO) Nanobridge-based Sensor Platform and Functionalization for Explosive Sensing

Report No. ARL-TR-5462
Authors: Ashley D. Mason and Brett H. Piekarski
Date/Pages: March 2011; 22 pages
Abstract: Nanowire (NW)-based sensors present an alternative to thin films for improved gas sensing because of their inherently high surface-to-volume ratio. Zinc oxide (ZnO) NWs have a well-developed vapor-phase growth method and can be seeded on carbonized photoresist (C-PR). The C-PR also acts as an electrical contact; however, a molybdenum (Mo) layer decreases contact resistance and masks C-PR areas where growth is not desired. The selectivity of the device is refined using chemical functionalization, starting with a parylene-A activation layer applied via chemical vapor deposition (CVD). We present images of the C-PR, Mo, and NW interfaces taken with a microscope and a scanning electron microscope (SEM), as well as atomic force microscopy (AFM) roughness data for the parylene-A coatings. Using the functionalization described here, an array of devices could be created using the same process with only the final layer of functionalization (end-node species) changing. The results gleaned from these experiments can aid in the search for a chemical-based sensor array.
Distribution: Approved for public release
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Last Update / Reviewed: March 1, 2011