Quantification of the bond-angle dispersion by Raman spectroscopy and the strain energy of amorphous silicon

Roura, P.; Farjas, J.; Cabarrocas, P. Roca i

Quantification of the bond-angle dispersion by Raman spectroscopy and the strain energy of amorphous silicon

Authors

Roura, P.

Farjas, J.

Cabarrocas, P. Roca i

Description

A thorough critical analysis of the theoretical relationships between the bond-angle dispersion in a-Si and the width of the transverse optical (TO) Raman peak is presented. It is shown that the discrepancies between them are drastically reduced when unified definitions for these magnitudes are used. This reduced dispersion in the predicted values of the bond-angle dispersion together with the broad agreement with its scarce direct determinations is then used to analyze the strain energy in partially relaxed pure a-Si. It is concluded that defect annihilation does not contribute appreciably to reducing the a-Si energy during structural relaxation. In contrast, it can account for half of the crystallization energy, which can be as low as 7 kJ/mol in defect-free a-Si.
24 pages, 5 figures, accepted for publication in J. Appl. Phys