Microstructure and Raman scattering of Ag-doping ZnO films deposited on buffer layers

• Optimization for ZnO growth is investigated.
• Proper doping concentration and substrate are critical for ZnO growth.
• Microstructure and Raman scattering properties are comprehensively studied.

Ag-doped ZnO (ZnO:Ag) films were deposited on ZnO buffer layers by radio frequency reactive magnetron sputtering. The effect of Ag doping content on the crystallization behavior and Raman scattering of the ZnO:Ag films have been studied. The crystal structures and surface morphology of the films were systematically investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results showed that ZnO films showed a stronger preferred orientation toward the c-axis and a more uniform grain size after appropriate Ag doping. Two additional local vibrational modes (LVMs) at 243.9 and 393.7 cm−1 induced by Ag dopant in ZnO:Ag films were observed by Raman analyses at RT, corresponding to Ag atoms located at O sites (LVM of Zn–Ag) and Zn sites (LVM of Ag–O) in ZnO lattice. Meanwhile, Raman analyses showed that Ag mainly substitutes on the Zn site.