Modification of SnO2 surface oxygen vacancies through Er doping for ultralow NO2 detection

Abstract Despite the high prevalence of tin oxide (SnO2) based sensors for detection of numerous toxic gases, they suffer from issues of cross-sensitivity and high operating temperatures. Herein, SnO2 lattice has been modified with highly catalytic erbium (Er) based rare earth metal to address aforementioned issues. Thin films of undoped and 1, 3, 5 wt% Er-doped SnO2 nanoparticles have been deposited by electron beam evaporation technique and influence of Er on structural and optical characteristics of SnO2 films has been investigated for gas sensing applications. The incorporation of Er in SnO2 thin films has been found to tune the concentration of oxygen vacancies, which can enhance the gas sensing parameters. The sensor with an optimized amount of Er (3 wt%) exhibits a maximum sensing response for 1 ppb of NO2 at room temperature (25°C) with improved selectivity and stability against humidity.