The role of chemisorption and physisorption in Fe-doped SnO2 acetone sensors

The gas sensing mechanism is one of the most important parameters of chemiresistive gas sensors, and distinguishing them opens the possibility of manipulating sensor performance. In this study, we introduced the concept of adsorption-type contribution to the gas-sensing performance that could further enhance the fundamental understanding of gas-sensing mechanisms and aid future sensor development. The proposed concept was applied for the examination of Fe-doped SnO 2 gas sensors ionic obtained through the successive layer adsorption and reaction (SILAR) method. The 0.5 mol.% Fe-doped SnO 2 sensor demonstrated a sensing response of 118% to 25 ppm acetone at a relatively low optimal working temperature of 175 °C, and a temperature-induced p–n junction shift at around 50 °C. It had an LOD of approximately 250 ppb and a linear sensing range that extended to 25 ppm. Notably, the sensor had a response time of approximately 52 s and a recovery time of around 14 s. These results suggest the potential of Fe-doped SnO 2 sensors for acetone detection relevant to self-diagnosis and health monitoring. • Fe-doped SnO2 thin films synthesized by SILAR method • 0.5 mol.% Fe doping gives highest acetone sensitivity at 175 °C • Limit of detection achieved as low as 250 ppb acetone • Response/recovery times of ∼52 s / 14 s were observed • Adsorption-type contribution concept introduced for gas sensing