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Micromachines 2017, 8(11), 333; https://doi.org/10.3390/mi8110333

Light-Activated Metal Oxide Gas Sensors: A Review

1
and
2,*
1
Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
2
Department of Biomedical Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
*
Author to whom correspondence should be addressed.
Received: 11 October 2017 / Revised: 8 November 2017 / Accepted: 13 November 2017 / Published: 18 November 2017
(This article belongs to the Special Issue Nanomaterials Based Sensors)

Abstract

Conductometric gas sensors facilitated by photons have been investigated for decades. Light illumination may enhance device attributes including operational temperature, sensing sensitivity and selectivity. This paper aims to provide an overview on the progress of light-activated gas sensors, with a specific focus on sensors based on metal oxides. The material systems that have been studied include pure metal oxides, heterostructures of semiconductor-metal oxides and metal-metal oxides, and metal oxides with dopant. Other reported works on the use of different nanostructures such as one-dimensional and porous nanostructures, study of sensing mechanisms and the interplay between various factors are also summarized. Possible directions for further improvement of sensing properties, through optimizing the size of nanomaterials, film thickness, light intensity and wavelength are discussed. Finally, we point out that the main challenge faced by light-activated gas sensors is their low optical response, and we have analyzed the feasibility of using localized surface plasmon resonance to solve this drawback. This article should offer readers some key and instructive insights into the current and future development of light-activated gas sensors. View Full-Text
Keywords: gas sensors; metal oxides; heterostructures; doping; light activation; one-dimensional nanostructures; porous nanostructure; localized surface plasmon resonance gas sensors; metal oxides; heterostructures; doping; light activation; one-dimensional nanostructures; porous nanostructure; localized surface plasmon resonance
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Xu, F.; HO, H.-P. Light-Activated Metal Oxide Gas Sensors: A Review. Micromachines 2017, 8, 333.

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