A study of hydrogen sensing properties and microstructure for highly dispersed Pd SnO2 thin films with high response magnitude

• Published in: Applied surface science Vol. 311; pp. 74 - 82
• Main Authors: Yang, Liu, Yin, Chenbo, Zhang, Zili, Zhu, Bin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 30.08.2014; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Detection; Exact sciences and technology; H2 gas sensing; Iron; Magnetron sputtering; Palladium; Physics; Sensors; SnO2 thin film; Sol gel process; Sol–gel; Surface modified; Thin films; Tin dioxide; Tin oxides; SnO2 thin film; Magnetron sputtering; Sol–gel; Surface modified; H2 gas sensing; gas sensing; Hydrogen; Sol-gel; H; Film growth; Thin films; Magnetrons; Cathode sputtering; SnO; thin film; Microstructure; Sol-gel process
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2014.05.003

•The thin films show a loosely packed and highly textured structure with Pd particles highly dispersed on the surface.•The Pd-surface-modified SnO2 thin films fabricated by magnetron sputtering have response magnitude of S=4636 toward 2000ppm H2 gas at 175°C.•The sensors also show a high response magnitude of S=738 toward 2000ppm H2 gas at the low temperature of 75°C.•The influence of the annealing process on the Pd-surface-modified SnO2 films was discussed for the first time.•An abnormal phenomenon of Pd modified SnO2 thin films was observed and explained. A series of SnO2-based thin films were prepared for hydrogen sensor fabrication. Pure, Pd-doped and Pd-surface-modified SnO2 thin films were deposited by magnetron sputtering. One Fe-doped, PEG-400-added, Pd-surface-modified SnO2 thin film was prepared by the sol–gel method. The structure, surface morphology and composition of the as-prepared SnO2 thin films were analyzed, and the H2 sensing performance of these films toward hydrogen gas in concentration of 100–2000ppm at operation temperature of RT-275°C were investigated. The Fe-doped, PEG-400-added, Pd-surface-modified SnO2 thin film prepared by the sol–gel method had a response magnitude of about 288 toward 2000ppm H2 at 275°C. It was the first time that Pd-surface-modified SnO2 thin films fabricated by magnetron sputtering exhibited a high response magnitude of 4636 and an extremely fast response time of about 1s to 2000ppm H2 at 175°C. Additionally, this sensor also showed a response magnitude of 738 toward 2000ppm H2 at the low temperature of 75°C. The influence of the annealing process on the Pd-surface-modified SnO2 thin films was discussed for the first time. The abnormal phenomenon of Pd modified SnO2 thin films that the initial resistance reaches a peak with increasing operation temperature was observed and explained.