Review—MOS-Based Benzene, Toluene, Ethylbenzene, and Xylene Gas Sensors

Gas sensing technology has evolved over the last 50 years but there has been a lacuna to understand the sensing mechanism. The understanding becomes even more complicated when gases like Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) are sensed using conventional gas sensors. BTEX gases have inert chemical behaviour, making it difficult to detect such gases using the widely explored metal-oxide-semiconductors (MOS). BTEX gases are generated in petroleum and other industries and hence their detection at low ppm is a necessity as it is carcinogenic in nature and possesses a threat to human health. For efficient sensing of such gases, a variety of materials including quantum dots, nano-flakes of different geometry, carbon-based materials etc. are being explored. This review focuses on the different materials and their properties which makes them efficient sensors to detect BTEX gases. Polymer-based materials are out of the scope of this review article as the topic deserves a separate article because of its vastness. In future scope, probable materials which can prove to be a good BTEX gas sensor are discussed.