Effects of hydrogen annealing on the microstructure and optical properties of single-phased Ag2O film deposited using direct-current reactive magnetron sputtering

Single-phased and (111)-oriented Ag₂O film deposited using direct-current reactive magnetron sputtering is annealed using different annealing temperatures (T_a) for 1 h in Ar and H₂ mixture. After hydrogen annealing, a very weak but clear Ag(200) diffraction peak begins to appear, and the Ag₂O diffraction peak weakens at T_a = 175 °C. However, the Ag diffraction peak becomes discernable at T_a = 190 °C. No Ag₂O diffraction peaks but rather Ag diffraction peaks are discerned at T_a = 200 °C. The hydrogen reduction effect can reduce the film's critical thermal decomposition temperature to 175 °C. After hydrogen annealing, the surface of the film evolutes from compact and uniform to osteoporosis, and then to a porous structure. Moreover, the optical properties of the film obviously change at T_a over 190 °C, indicating that the hydrogen reduction can significantly enhance the decomposition of Ag₂O due to H₂ dissociation on the surface followed by gaseous H₂O molecule formation and desorption.