Paper EM1-MoA9
Analysis and Application of Hybrid Electronic Structures Formed by Nanoscale Conductive Coatings on Textiles

Monday, October 31, 2011, 4:40 pm, Room 209

Electronic functionalization of complex fibrous systems is of interest for developing new hybrid electronic systems geared toward integrating biological detection and energy harvesting devices in textile materials. Reliable methods to evaluate the electrical properties of these textiles are necessary for future device design and performance improvement. This work investigates conformal, nanoscale coatings of zinc oxide and tungsten produced by atomic layer deposition (ALD) on natural and synthetic fibers structures, resulting in novel hybrid-based electronic structures. A modified 4-probe test method is introduced to evaluate the effective conductivity of these coatings. An applied normal force orthogonal to the current and field direction improves the fiber/fiber contact, resulting in consistent evaluation of the effective conductivity of the coatings across fiber systems and is a unique method of evaluating the mechanical behavior of these coated fiber structures. Optimization of the coatings has resulted in conductivity values as high as 40 S cm^-1 for zinc oxide coatings (~75 nm) on polypropylene and cotton fiber, as well as 1150 S cm^-1 for ALD tungsten (~50 nm) on quartz fiber matrices. Device application of these coated fiber matrices are benefited by their “all-fiber” structure, with characteristic high porosity and surface area. For example, a textile-based flow-through metal-insulator-metal capacitors fabricated from tungsten-coated quartz fibers is shown as an application in liquid chemical sensing. The mechanisms related to electron transport in a surface-coated textile fabric and implications on device fabrication and improvement will be discussed.