Selective Formations of Antimony-dopant for Highly Sensitive Nitrogen Dioxide Responsive Behavior of Tin Oxide-based Chemiresistive Sensor

Abstract

Here, selective formation of antimony (Sb) dopant species responsible for highly sensitive gas sensors based on tin oxide (SnO₂) film grown via pulsed laser deposition is presented. By elevating a forming energy through controlling substrate temperature, not only crystallinity of Sb-SnO₂ (ATO) is notably enhanced but the Sb⁵⁺ also predominantly replace at Sn⁴⁺ site rather than Sb³⁺ counterpart. Such Sb-species selection plays a crucial role on the density of oxygen vacancy and free electron enabling to rationally design conductive behaviour of ATO film from insulative to degenerated semiconductor. As a practical example, detection of nitrogen dioxide (NO₂) gas is selected as an application model. We found a narrow window for high NO₂ sensing performance of ATO film which strongly corresponds with the amount of carrier density. At certain window, ATO film exhibits high NO₂ response of 24.65 (10 ppm) and low limit of detection of 0.5 ppm, which is 5-fold higher and 10-fold lower than that of undoped-SnO₂, respectively. Our finding demonstrates a facile approach to design over the chemical state, defect, and conductivity of the active sensing layer, allowing us to achieve an excellent sensing performance of functional materials conjugated to a nano-electronic platform.