Effects of the sputtering power on the crystalline structure and optical properties of the silver oxide films deposited using direct-current reactive magnetron sputtering

This paper reports that a series of silver oxide (Ag_xO) films are deposited on glass substrates by direct-current reactive magnetron sputtering at a substrate temperature of 250 oC and an oxygen flux ratio of 15:18 by modifying the sputtering power (SP). The Ag_xO films deposited apparently show a structural evolution from cubic biphased (AgO + Ag₂O) to cubic single-phased (Ag₂O), and to biphased (Ag₂O + AgO) structure. Notably, the cubic single-phased Ag₂O film is deposited at the SP = 105 W and an AgO phase with <220> orientation discerned in the Ag_xO films deposited using the SP > 105 W. The transmissivity and reflectivity of the Ag_xO films in transparent region decrease with the increase the SP, whereas the absorptivity inversely increases with the increase of the SP. These results may be due to the structural evolution and the increasing film thickness. A redshift of the films' absorption edges determined in terms of Tauc formula clearly occurs from 3.1 eV to 2.73 eV with the increase of the SP.