Effect of the femtosecond laser treatment of hydrogenated amorphous silicon films on their structural, optical, and photoelectric properties

Nanocrystals Growth Control during Laser Annealing of Sn:(α-Si) Composites

“…Note that crystallization of amorphous Si under the influence of laser radiation has been observed by many researchers [31][32][33][34]. It is believed that laser-induced crystallization proceeds through local heating of -Si by laser beam to a temperature above 1000 ∘ C [31][32][33], or due to the so-called "cold melting" of Si under short but powerful laser pulses (10 11 -10 12 W cm −2 ) [34][35][36]; in any case the crystallization is considered to proceed through a thermal mechanism. However, in our case the laser power was not high enough for a pure thermal crystallization.…”

Giant birefringence and dichroism induced by ultrafast laser pulses in hydrogenated amorphous silicon

“…21 Transforming amorphous silicon (a-Si) into a nanocrystalline form through ultrafast laser irradiation has already been demonstrated (nc-Si). [22][23][24][25][26][27][28][29][30][31] In this letter, we demonstrate that the ultrafast laser assisted nanocrystallization of a-Si:H is accompanied by the formation of a laserinduced periodic structure. The observed pattern with the subwavelength modulation of the complex refractive index exhibits a dichroism and enhanced form birefringence, which is two orders of magnitude higher than commonly observed in uniaxial crystals such as quartz, ruby, sapphire, or femtosecond laser nanostructured silica glass.…”

Raman Scattering in the Process of Tin-Induced Crystallization of Amorphous Silicon

“…The latter band survives in further measurements carried out at the lower irradiation power a lot of researchers [24][25][26][27][28][29]. It is agreed that, after a local heating of a-Si by a laser beam to temperatures higher than 1000 ∘ C [24][25][26] or the so-called "cold melting" of Si under the influence of short, but powerful laser pulses (10 11 ÷10 12 W/cm 2 ) [27][28][29], a thermally induced crystallization takes place. However, in our case, the power of a laser beam was insufficient for the thermal crystallization.…”

“…At the same time, in the spectra for region A (above the layer of metallic tin), besides the band of amorphous silicon state at 2 = 0.5 0 , there arises and grows, at 3 = 0 , an additional narrow band in the interval 490-500 cm −1 , which corresponds to the nanocrystalline phase of silicon [22,23]. The latter band survives in further measurements carried out at the lower irradiation power a lot of researchers [24][25][26][27][28][29]. It is agreed that, after a local heating of a-Si by a laser beam to temperatures higher than 1000 ∘ C [24][25][26] or the so-called "cold melting" of Si under the influence of short, but powerful laser pulses (10 11 ÷10 12 W/cm 2 ) [27][28][29], a thermally induced crystallization takes place.…”