Atomic Layer Deposition to Materials for Gas Sensing Applications

Abstract

Atomic layer deposition is a thin film deposition technique based on self-terminated surface reactions. Contrarily to most of the thin film deposition techniques, it is not a line of sight deposition technique due to the sequential introduction of the gaseous precursors and because the reactants can only react with surface species. The precursors can thus diffuse into porous structures and the conformal coating of high aspect ratio structures can be achieved. Because of these peculiarities, atomic layer deposition is an attractive technique for fabricating materials to be applied in resistive gas sensors. This article focuses on materials for resistive gas sensor devices in which the sensing material is elaborated using atomic layer deposition, in at least one step of the fabrication. It will be shown that atomic layer deposition has proven to be well-suited for the elaboration of compact thin films, nanostructures, and heterostructures to be applied for the detection of a variety of analytes such as toxic compounds, pollutants, explosives, etc. The chemical and physical properties of the sensing layers will be discussed in parallel to the gas sensing mechanisms in an attempt to develop clear structure–property correlations.