A review of advanced gas sensor based on sputtering SnO2 thin film— challenges and opportunities

Micro Electro Mechanical System (MEMS) gas sensors based on sputtered SnO2 thin films have been widely studied for emitted gases and VOCs due to their advantages such as low cost, small size, and high sensitivity. In this review, authors review articles focusing on the influence of sputtering parameters on sputtered SnO2 thin films, in which the influence of sputtering angle, pressure, power, and atmosphere, and substrate temperature, and film thickness are discussed in depth in the context of their effects on the physical properties of the sputtered SnO2 thin films. Subsequently, the practical utilizations of gas sensors based on sputtered SnO2 thin films for detection of H2, VOCs, H2S, NO2, and NH3 are also discussed. The research advances and inadequacies of the sensors are summarized from the perspective of practical commercial gas sensors. Furthermore, the challenges and opportunities for gas-sensing film based on sputtered SnO2 films are addressed. Particularly, how to decrease the optimal working temperature is theoretically analyzed.