Structural information from the Raman spectrum of amorphous silicon

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

“…When the FWHM and ⌬ G are converted into ͑⌫ / 2͒ and ⌬ respectively, the corrected relationship of Maley is very close to that of Beeman-Tsu. This coincidence is very reassuring because, although the microscopic models used by Maley et al 14 were similar to those of Beeman et al, 9 different polarizability mechanisms were assumed. Finally, a model calculation without adjustable parameters by Marinov and Zotov 15 gave ͑⌫ / 2͒ =40 cm −1 ͑FWHM= 90 cm −1 ͒ for a model with ⌬ = 10.8°, in exact agreement with the Beeman-Tsu formula ͓Eq.…”

“…For this reason, the rest of the results plotted in Fig. 1 take the work of Beeman et al 9 as reference. The reduced Raman spectrum,I red ͑ ͒, with the thermal and harmonic oscillator factors removed, can be expressed as the product of the vibrational density of states, g͑ ͒, and a coupling parameter C͑ ͒,…”

“…Except for the one by Tsu et al, 8 all of them have been obtained by numerical simulation of the Raman spectra on a series of microscopic models of a-Si. Beeman et al 9 made the first calculations with the aim of confirming the validity of the relationship of Tsu et al,…”

Relaxation and derelaxation of pure and hydrogenated amorphous silicon during thermal annealing experiments

“…4 Below 6.6°, no models can be built, i.e., a configurational gap is predicted between the allowed microscopic configurations of a-Si ͑⌬ Ͼ 6.6°͒ and c-Si ͑⌬ =0͒. This value has not been experimentally reached to date, and the question arises of whether this discrepancy is because the ⌬ value of the relaxed state is higher than predicted, or it is due to kinetic reasons.…”

“…3͒ by using the following particular relationship of Beeman et al: 4 ⌫/2͑in cm −1 ͒ = 7.5 + 3⌬ ͑in deg͒. ͑1͒…”