Local vibrations of oxygen in Ge crystals grown by the Czochralski method adopting liquid-B 2O 3 encapsulation and GeO 2 powder doping were investigated by Fourier-transform infrared spectroscopy. Strong absorption peaks at 855 cm -1, originating in local vibration of interstitially dissolved oxygen O i as Ge-O i-Ge quasi-molecules, developed depending on the doped amount of GeO 2. Similarly, an absorption peak related to the combined vibration of Ge-O i-Ge was found at 1264 cm -1 and the conversion factor from the peak intensity to the oxygen concentration was evaluated to be 1.15×10 19 cm -2. By prolonged annealing at 350 °C an absorption peak developed at 780 cm -1, indicating formation of oxygen-related thermal donors. From the variations of carrier density and oxygen concentration, one donor was found to possess about 15 O i atoms.
- Local vibration
- Optical properties
- Thermal donor
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering