Effect of Substrate Temperature on the Structural and Raman Properties of Ag-Doped ZnO Films

Ag-doped ZnO (ZnO:Ag) films are prepared on c-plane sapphire substrates by pulsed laser deposition at different substrate temperatures. The effect of substrate temperature on the ZnO:Ag film is studied in detail by EDX, XRD and Raman spectroscopy. The results reveal that raising the substrate temperature is beneficial for incorporating Ag into ZnO:Ag films in the range of our experimental temperatures and a number of Ag atoms incorporation into ZnO:Ag films may cause the (002) peak positions of the XRD spectra shift to a lower angle direction, but hardly affect the c−axis orientation of the films. The (002) peak shift ought to be due to the increase of lattice constant in the c−axis direction caused by the partial substitution of Zn²⁺ ions by Ag⁺ ions. In addition, a local vibrational mode (LVM) at 492 cm⁻¹ induced by doping Ag occurred in the Raman spectra of all the ZnO:Ag films and its peak position hardly shifted with increasing substrate temperature. It means that the LVM can act as an indication of Ag incorporation into ZnO:Ag film.