Copper(II) oxide nanowire array hydrogen sensor via facile large area contact integration

This paper presents a novel method to achieve large area contact integration for copper(II) oxide (CuO) nanowire array-based hydrogen gas sensors, which provides a simple solution to the ongoing challenge of harvesting nanostructured materials for gas sensing applications. The method presented herein offers six distinct advantages over previous nanostructured gas sensing technologies: (1) convenient electrical access to as-grown, freestanding nanowire arrays, thereby obviating postgrowth thin-film metallization, (2) lithography-free fabrication, (3) usage of large area nanowire arrays to circumvent low yield of single nanowire sensors, (4) reusability of contacts for batch characterization, (5) compatibility with all free-standing arrays grown on electrically conductive substrates, and (6) rapid response and recovery times. The CuO nanowire array-based gas sensors exhibited 5× to 25× increased resistance during operation, and a 20× improvement in recovery time compared to prior works.