Effect of substrate temperature on microstructure and optical properties of single-phased Ag2O film deposited by using radio-frequency reactive magnetron sputtering method

Using a radio-frequency reactive magnetron sputtering technique, a series of the single-phased Ag₂O films are deposited in a mixture of oxygen and argon gas with a flow ratio of 2:3 by changing substrate temperature (T_s). Effects of the T_s on the microstructure and optical properties of the films are investigated by using X-ray diffractometry, scanning electron microscopy and spectrophotometry. The single-phased Ag₂O films deposited at values of T_s below 200 oC are (111) preferentially oriented, which may be due to the smallest free energy of the (111) crystalline face. The film crystallization becomes poor as the value of T_s increases from 100 oC to 225 oC. In particular, the Ag₂O film deposited at T_s = 225 oC loses the (111) preferential orientation. Correspondingly, the film surface morphology obviously evolves from a uniform and compact surface structure to a loose and gullied surface structure. With the increase of T_s value, the transmissivity and the reflectivity of the films in the transparent region are gradually reduced, while the absorptivity gradually increases, which may be attributed to an evolution of the crystalline structure and the surface morphology of the films.