Raman Spectrum of Wurtzite Silicon

Relationship between Raman crystallinity and open-circuit voltage in microcrystalline silicon solar cells

“…In our samples, it exhibits a maximum centred at a mean value of 51871 cm À1 , and has a mean full-width at half-maximum (FWHM) value of 1071 cm À1 . This peak frequently exhibits a tail towards smaller wavenumbers (around 510 cm À1 ): a tail that has, in the literature, been attributed either to crystallites of diameters lower than 10 nm [12], or to a silicon Wurzite phase [13], that could result from twinning defects [2]. In our deconvolution procedure, this tail is fitted with a peak at 510 cm À1 , bounded between 505 and 515 cm À1 (in order to avoid a competition between the 510 cm À1 and the 480 cm À1 peaks during the fit, as observed in Ref.…”

Synthesis of Silicon Nanowires with Wurtzite Crystalline Structure by Using Standard Chemical Vapor Deposition

“…In contrast, Si NWs exhibit a sharp peak centered at 503 cm -1 , as well as a broad band between 223 and 288 cm -1 , in excellent agreement with the predicted TO and the 2-fold transversal acoustical (TA) modes of wurtzite Si. [18][19][20][21] While the shift of the TO mode to 503 cm -1 could be attributed to a shorter correlation length as in the case of nanocrystalline Si, the TA modes at 223 and 288 cm -1 correspond exclusively to the presence of wurtzite Si and cannot be confused with Si with the former, as the TO mode normally does not shift with a decrease of the correlation length. [22] The extreme example of that would be nanocrystalline Si, where the TA peak does not move from 300 cm -1 , while the TO peak can shift down to 510 cm -1 .…”

Raman Spectroscopy on Semiconductor Nanowires

“…This, together with the slightly different lattice parameter should lead to different vibrational properties. Nevertheless -as it has been shown in the case of GaN, SiC and Si -the phonon dispersion of hexagonal structure can be deduced with good accuracy from the phonon dispersion of the cubic one by just considering the different stacking of the 'abc' and 'ab' layers (Harima, 2002;Loudon, 2001;Kobliska & Solin, 1973). The phonon dispersion of the cubic structure along the [111] direction corresponds to the Г L direction in the Brillouin zone.…”