Noticeable enhancement in NH3 sensing performance of nebulizer spray pyrolysis deposited SnO2 thin films: An effect of Tb doping

Abstract

Rare metal Terbium (Tb) doped SnO 2 (SnO 2 :Tb) films were fabricated via spray pyrolyzed method with different doping concentrations. The effects of terbium doping concentration on its microstructural, optical, photoluminescence , and room temperature ammonia vapor sensing properties were reported. The crystallite size of the prepared Tb-doped tin oxide films decreases with an increase in doping concentrations. The obtained crystallite size ranges from ~ 12 – 9 nm. The terbium incorporation was confirmed by EDS and elemental mapping. The bandgap values are enhanced as the concentration of Tb doping increases. The high gas response of 79% with fast response/recovery of 31/11 s , respectively is reported for 25 ppm of ammonia at room temperature for 5% Tb doped sample. The gas sensing cycle test shows the excellent sensitive behavior of the films without any decrease upon 5 repeated cycles. The stability of the sample was also checked for a corresponding Tb 5% doped sample, which revealed a stable response even for 50 days. • Novel SnO 2 :Tb thin films were fabricated facilely by nebulizer spray pyrolysis technique. • XRD study confirm monophasic rutile tetragonal films fabrication at all Tb contents. • Energy gap was enhanced from 3.63 to 3.76 eV on Tb doping in SnO 2 . • The highest response/quick recovery time of 31s/11s was noticed for 5 wt% SnO 2 :Tb films at 300K. • The stability of 5 wt% SnO 2 :Tb film was tested and noticed a stable response even for 50 days.