Classification of workplace gases using temperature modulation of two SnO₂ sensing films on substrate

Two SnO₂-based sensing films (pure SnO₂ and SnO₂/Pt) and a Pt thin film as a temperature sensor were fabricated on an alumina substrate for classifying workplace environmental gases. By controlling the heating power in the shape of a trapezoid, a temperature profile of the SnO₂ sensing films was created along with four unique sensing response curves to the tested gases. A principal component analysis (PCA) was performed using variables extracted from the sensing response curves. The results confirmed that the sensor array with the proposed operating mode was extremely effective in classifying workplace environmental gases, such as CO₂, C₃H₈, and C₄H₁₀.