Room-Temperature Hydrogen Sensing Properties of SnO2 Thin Films Fabricated by the Photochemical Deposition and Doping Methods

Abstract

SnO2 thin films were fabricated by photochemical deposition (PCD) method for application as a hydrogen gas sensor. The aqueous growth solution contained 10 mmol/L SnSO4, and the pH was adjusted to 2 by addition of HNO3. The growth solution was dropped onto the glass substrate and irradiated using an ultrahigh-pressure mercury arc lamp. To enhance the sensitivity to hydrogen, Pd was doped by a novel photochemical doping method, in which PdCl2 solution was dropped onto the film and irradiated. The photo-Pd-doped films showed an increase in current of about five orders of magnitude at room temperature in 0.5% hydrogen ambient compared with in vacuum. Thus, photo-Pd-doped PCD-SnO2 films operate as a highly sensitive room-temperature hydrogen gas sensor.