Selectivity and Sensitivity Property of Metal Oxide Semiconductor Based Gas Sensor with Dopants Variation: A Review

This review paper exhaustively explores metal oxide semiconductor (MOS) gas sensors with prime focus to explore the ways for performance enhancement of a gas sensor. The paper discusses various aspects for a sensor and encompasses with several other gas sensors extensively. The fabricated sensors that are reported in the literature are compared and analyzed for a better understanding to the effects of different dopants with different MOS thin films. The present study is confined to the gases that are either highly toxic or inflammable in nature. The performance attributes like sensitivity, selectivity, as well as the stability of MOS gas sensors are influenced by a number of factors, that are discussed. The dopant-induced changes in MOS materials used in the gas sensing are also elaborated in the paper. The present study reveals the effect of dopant atoms to the structural and optical properties as well as the selectivity and sensitivity for particular metal oxides semiconductor and few semiconductor thin films. Dopants alter the microstructure and morphology of MOS, as well as their activation energy, optical absorption, and band gap, enhancing their characteristics for gas detection. Dopants may cause defects in MOS by creating oxygen vacancies. These defects improve the gas sensing capabilities. This study also looked at a variety of nanostructures. Finally, examples of MOS are provided to show how different MOS materials can be used for gas sensing. The review recognizes various aspects that can be utilized for enhancements of selectivity and sensitivity towards a particular gas for a sensor.