Decay mechanism of the nu(3) 865 cm(-1) vibration of oxygen in crystalline germanium

The nu(3) (862.5 cm(-1)) vibration of oxygen in crystalline germanium is shown to decay into one nu(1) local mode of the oxygen center plus two lattice modes. This description predicts increases in the linewidths in O-16-doped germanium, and decreases in the linewidths in O-18-doped germanium, as the Ge mass in the Ge-O-Ge complex increases, in agreement with observation. The decay time is expected to vary only slightly with the isotope of oxygen, as observed, and the smallest reported linewidths are consistent with the measured decay times

Strange lifetimes of the vibrations of interstitial oxygen in SiGe alloys

The transient-bleaching decay time of the v(3) (1136 cm(-1)) band of oxygen in Si1-xGex alloys, at low temperatures, is found to increase rapidly from a few tens of picoseconds when x = 0, to 125 ps when x is in the range 0.011-0.066. We show that the increased decay time is caused partly by perturbations of the oxygen by the Ge, and partly by the small decrease in the frequencies of the lattice modes in the alloy. The decay time of v(3) in crystalline germanium (x = 1) is also similar to 115 ps, similar to that for the dilute alloys, but it is shown to occur through a different three-phonon process