We studied ultrafast relaxation of localized excited states at Ge-related oxygen deficient centers insilica using femtosecond transient-absorption spectroscopy. The relaxation dynamics exhibits abiexponential decay, which we ascribe to the departure from the Frank–Condon region of the firstexcited singlet state in 240 fs, followed by cooling in ~10 ps. At later times, a nonexponentialrelaxation spanning up to 40 ns occurs, which is fitted with an inhomogeneous distribution ofnonradiative relaxation rates, following a chi-square distribution with one degree of freedom. Thisreveals several analogies with phenomena such as neutron reactions, quantum dot blinking, orintramolecular vibrational redistribution. © 2008 American Institute of Physics.[DOI: 10.1063/1.2975965]
|Numero di pagine||3|
|Rivista||Applied Physics Letters|
|Stato di pubblicazione||Published - 2008|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)
Leone, M., Portuondo-Campa, Callegari, Gawelda, Chergui, M., Cannizzo, A., & Van Mourik (2008). Relaxation processes of point defects in vitreous silica from femtosecondto nanoseconds. Applied Physics Letters, 93, 102901_1-102901_3.