Magnetron radio frequency sputtering growth of LaNi5 thin films and their hydrogen-sensitive properties at room temperature and ordinary pressure

In this study, polycrystalline LaNi5 thin films were prepared by a co-sputtering method. Structural changes in the films were investigated by XRD analysis. After annealing, hydrogen-sensing performance of LaNi5 thin films were examined at room temperature and ordinary pressure. Sensitivity, response, and recovery times upon exposure of LaNi5 thin films at different hydrogen gas concentrations were determined. To investigate sensitivity intrinsically, changes in the microstructure and material composition of LaNi5 thin films were characterized by scanning-electron microscopy, x-ray energy-dispersive spectroscopy, and x-ray photoelectron spectroscopy. Results show that LaNi5 thin films have improved hydrogen-sensing properties, which could be attributed to the assistance of La(OH)3-La2O3-Ni on the absorption-desorption process. In conclusion, sputtered and annealed LaNi5 thin films exhibit significantly improved hydrogen sensitivity at room temperature and ordinary pressure compared with other LaNi5 materials used in previous studies.