Owing to the significant emission of Volatile Organic Compound gases (VOCs) by the oil and natural gas industry and considering the adverse health and environmental effects associated with VOCs exposure, the need for implementing accurate and real-time VOC sensors in air quality monitoring systems is crucial. In the last few decades, various methods have been developed for detecting VOC gases. Out of all of the developed methods, Metal Oxide Semiconductor (MOS) sensors are the most known for their usage as cheap, accurate, and disposable sensors for sensing VOCs in many industrial applications. Due to its high bandgap energy, tin oxide (SnO2) is considered as one of the best materials to manufacture a MOS sensor. Up to now, extensive research has been done on optimizing the SnO2-based gas sensor performance;​ however, to the best of our knowledge, less attention has been paid to optimizing an ALD-deposited SnO2 thin film as a sensing layer. Moreover, the relationship between the target gas polarity and the mentioned optimization has not been investigated before.

In this study, we present an extensive characterization of an atomic-layer-deposited SnO2 -based thin film gas sensor to detect selected polar and non-polar VOCs, namely ethanol, acetone, and toluene, for a concentration range of 20- 227 ppm. The deposited SnO2 thin film with an approximate thickness of 40 nm showed the highest response to target VOCs, irrespective of the operating temperature or the target VOC polarity. Importantly, our results suggested that the operating temperature of the sensor was dependent on the polarity of the target analytes. The developed SnO2-based MOS sensors can therefore be tuned to selectively differentiate between target gases based on their polarity. This can be advantageous for detecting mixtures of polar and non-polar VOCs. A good example of a practical application for selective detection of mixture of VOCs can be in Natural Gas-related industries to analyze the gas components and optimizing the odorization system.