Experimental and Theoretical Insights on the O Ptical and Morphological Properties of Germanium Oxide Thin Films Deposited Via Rf Magnetron Sputtering

In this study, the optical and morphological properties of germanium oxide (GeO 2 ) thin films have been investigated by experimental and theoretical methods. The films were produced by reactive radio frequency magnetron sputtering (RFMS) under varying oxygen partial pressures ratio to the total pressure, 2%, 4%, 6%, 8%. The optical and structural properties of the films grown have been studied experimentally and theoretical calculations have been presented using density functional theory (DFT). As the x-ray diffraction (XRD) analysis is considered, Ge (111) peak has been observed in the films produced at 2% oxygen partial pressure ratio compared to all the other films has determined to be amorphous. Except for 2% film, the other films were annealed at 900°C, and as a result, GeO 2 (101), GeO 2 (110), GeO 2 (102) and GeO 2 (111) peaks were observed. The 2% film was annealed at different annealing temperatures (800, 850, 900, 950°C). As a result, the crystal property has changed compared to the others. It was found that the optical properties of the films grown are strongly dependent on the O 2 pressures used. Although the 8% film has a fairly sharp absorption edge, the others are bad. The energy band gap increased with increasing oxygen. After annealing at 900°C, the absorption edge of the films showed a sharp behavior except 4%. There are Ge-O-Ge antisymmetric stretching peaks appeared at 861.51 cm -1 , 949.94 cm -1 and symmetric stretching of hexagonal peaks at 516.34 cm -1 , 546.29 cm -1 , 581.95 cm -1 . The results of Density Functional Theory calculations are in good agreement with experimental observations.