Combinatorial gas phase electrodeposition for fabrication of three-dimensional multimodal gas sensor array

Abstract

This article introduces a programmable gas phase nanoparticle electrodeposition concept which enables the fabrication of multi-modal conductometric gas sensor arrays. The sensor application requires the deposition of more than one nanoparticle type to achieve orthogonal sensing capabilities and multi gas sensitivity and selectivity. The demonstrated “electronic nose” like array contains 1080 freeform point-to-point gas sensitive nanobridges of platinum, nickel oxide and gold based electrical connections on a single chip. The introduced architecture is different from previous reports; instead of two-dimensional thin metallic films, each gas sensitive bridge is a three-dimensional (3D) structure, which in turn, is composed of a porous but electrically conducting nanoparticle network. It was found that this architecture is unique since it does not require external heating to function. A multimodal sensor array will be demonstrated to detect various levels of Ammonia (NH3), Carbon Monoxide (CO) and Hydrogen Sulfide (H2S). Gas phase nanoparticle electrodeposition method uses a spark discharge-based nanoparticle source in combination with biased surface electrodes and charged photoresist patterns to accomplish the required programmable site selective deposition. The nanobridges form through nearest neighbor coulombic interaction.