Fig. 1. X-ray diffraction patterns of Ge films: (a) before annealing, (b) after annealing.

Fig. 2. Raman spectra of Ge films: (a), (b), (c) before annealing, (d) after annealing.

Fig. 3. Thickness at different deposition temperatures: (a) before annealing, (b) after annealing.

Fig. 4. Transmittance of Ge films on fused quartz: (a) before annealing, (b) after annealing.

Fig. 5. Optical band gap of Ge films on fused quartz: (a) before annealing, (b) after annealing.

Fig. 6. XPS analysis of Ge films after annealing: (a), (d) deposition (100°C) + annealing, (b), (e) deposition (200°C) + annealing, (c), (f) deposition (300°C) + annealing.