A gas sensor working at room temperature shows great potential in practical applications due to its lower energy consumption, good stability, high security and ease of miniaturization. World-wide efforts have been devoted to explore materials with excellent room-temperature gas sensing performance. Metal oxide semiconductor materials are widely sourced, environmentally friendly and flexible in structure control. Research of metal oxide semiconductor based sensors operated at room temperature has made significant progress recently. In this paper, the development process and working principle of metal oxide gas sensors are introduced, various metal oxide nanostructures in regard to their room-temperature gas sensing properties are comprehensively reviewed. Particular emphasis is given to those effective strategies for constructing room-temperature sensors and their sensing mechanism. Finally, some future research perspectives in the field of room-temperature sensors are discussed as well.

Contents

1 Introduction

2 Development process of MOS gas sensors

3 Working principle of MOS gas sensors

4 Construction of nanostructured MOS gas sensors with room⁃temperature sensing performance

4.1 Pure metal oxide nanostructures

4.2 Metal oxide hetero⁃ or composite⁃nanostructures

4.3 UV assisted gas sensing material

5 Conclusion and outlook