Sensors based on tin dioxide thin films for the detection of pre-explosive hydrogen concentrations

[Display omitted] •Complex studies were performed of H2 sensors based on thin SnO2 films with the Pt addition in the bulk.•Effect of the additive Pt on the sensor’s properties was study by AFM, XPS and Raman.•The fabricated of sensor for detecting pre-explosive concentrations of 0.1–2.5 vol % H2.•The sensor parameters remain stable during long-term testing after 50 days. In this work, novel semiconductor sensors were developed for detecting high pre-explosive concentrations of H2 (0.1–2.5 vol%) with high selectivity and stability. The sensors were based on thin (∼100 nm) nanocrystalline SnO2 films produced by magnetron sputtering of dispersed Pt and Pd layers deposited on the surface and addition of 13–14 at% Pt in the bulk. Studies on their nanostructure, composition, electrical properties, and gas-sensitive characteristics were carried out. X-ray photoelectron and Raman spectroscopies revealed that in the process of stabilizing annealing in Pt/Pd/SnO2:Sb,Pt film platinum introduced into the bulk segregates on the surface of the SnO2 microcrystals in the form of Pt° metal clusters and dispersed Pt2+ ions. The dispersed Pt2+ ions form bonds with lattice oxygen and contribute to the overlap of conduction channels. In the sensor subjected to annealing at Tan1 =723 K and Tan2=873 K, the optimal situation is realized when under the action of low (n < 0.1 vol%) H2 concentrations, the condition 2d0 = dM is satisfied and G1/G0 = 9–12. In the range of 0.1–2.5 vol% H2, narrowing of the space-charge region favors the formation of a conducting layer, and at 2d0 ≤ dM there is a sharp increase in the values of the responses to G1/G0 = 220–250 at 2.5 vol%.