Incompatibility of Pure SnO₂ Thin Films for Room-Temperature Gas Sensing Application

Despite the high sensitivity and selectivity, the high operating temperature required for activation energy of tin oxide (SnO₂) still stands as a drawback for SnO₂ based gas sensors. In this work, the SnO₂ thin films were deposited through spray pyrolysis and were subjected to gas sensing at 27 °C (room temperature) towards different gases. The films exhibited a consistently low response of approximately 1 when tested to various VOCs. The type, concentration, and mobility of charge carriers were determined from the Hall measurements. The high carrier concentration accompanied by poor mobility and grain boundary scattering is supposed to hinder its performance at room temperature. The obtained film had spherical morphology, which lead to grain boundary scatterings and decreased the mobility of carriers.