Highly-sensitive H2 sensor operating at room temperature using Pt/TiO2 nanoscale Schottky contacts

Abstract

Despite growing demands for high performance hydrogen (H-2) sensors operating at low temperature, metal oxides-based H-2 sensors intrinsically require an elevated operating temperature due to a high activation energy for gas adsorption on metal oxides surface. Here, we present a highly-sensitive H-2 sensor operating even at room temperature, enabled by the Pt/TiO2 nanoscale Schottky contacts which utilizes sensitive modulation of the Schottky barrier height by dissociative H-2 adsorption on the catalytic Pt layer, followed by the dipole layer formation at the junction. Our device showed very high H-2 response and short response and recovery times at low temperatures which are attributed to the unique device architecture having the highly-porous nanoscale Schottky contacts facilitating the gas diffusion and dissociation, and the top-and-bottom electrodes configuration making effective current modulation. Based on our results, we propose Schottky contact-assisted H-2 sensing mechanisms and a promising approach to further improve H-2 sensing performance at room temperature. (C) 2016 Elsevier B.V. All rights reserved.