Abstract
Triplet electron-hole excitations were introduced into amorphous silica to study self-trapping (localization) and damage formation using density functional theory. Multiple self-trapped exciton (STE) states are found that can be differentiated based on the luminescence energy, the localization and distribution of the excess spin density of the triplet state, and relevant structural data, including the presence or absence of broken bonds. The trapping is shown to be affected by the relaxation response of the silica network, and by comparing results of quartz and amorphous silica systems the effects of the inherent disordered structures on exciton self-trapping are revealed. A key result is that the process of exciton trapping can lead directly to the formation of point defects, without thermal activation. The proposed mechanism includes a non-radiative decay from the excited to the ground state followed by structure relaxation to a defect configuration in the ground state.
| Original language | English |
|---|---|
| Pages (from-to) | 2589-2595 |
| Number of pages | 7 |
| Journal | Journal of Non-Crystalline Solids |
| Volume | 352 |
| Issue number | 23-25 |
| DOIs | |
| Publication status | Published - 15 Jul 2006 |
Bibliographical note
Funding Information:This work was supported by the Office of Basic Energy Science, Department of Energy. The research was carried out at the University of Washington and at the William R. Wiley Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy, Office of Biological and Environmental Research located at Pacific Northwest National Laboratory. Battelle operates the Pacific Northwest National Laboratory for the Department of Energy.
Other keywords
- 61.72.Bb
- 61.72.Ji
- Defects
- Density functional theory
- Silica