Femtosecond laser induced crystallization of hydrogenated amorphous silicon for photovoltaic applications

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

“…According to Zanzucchi et al, 33 "Type 0" regime appears due to enhanced optical absorption in visible spectrum and is attributed to the hydrogen (H) release. The Raman analysis of the wagging vibrations of Si-H studied elsewhere 31 confirms that the H release starts at the energies below 0.02 lJ, and at 0.03 lJ its content drops to 20% of the initial value.…”

“…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.…”

“…Specifically, at the initial stage of the irradiation, the intense femtosecond pulses generate more defects (in comparison with picosecond ones) by reducing the hydrogen content in the lattice. Assuming that most of the hydrogen is released before the crystallization and laser-induced nanostructuring, 31 the absorption of the film increases drastically. This is because the absorption coefficient of the produced aSi (at photon energy of $1.2 eV) is almost two orders of magnitude higher than the nc-Si and four orders higher than the a-Si:H, 32,35-38 i.e., a-Si defines the efficiency of the subsequent modification regimes.…”

Nonlinear optical properties of metal nanoparticles: a review

“…15 In the past two decades, efficient nonlinear optical materials have made signicant progress in laser technology, and these materials have large nonlinear optical properties and a fast nonlinear response for various photonic and optoelectronic applications such as laser ablation, pulsed laser deposition, optical communication, optical information processing, and optical data storage and as optical limiters. [16][17][18][19][20][21] Optical limiting is one of the most promising practical applications of all nonlinear optical properties and can be used to protect the human eye and photosensitive components of delicate optical instruments from damage caused by intense optical radiation. 22 Optical limiters strongly attenuate a potentially dangerous laser beam while exhibiting a transmittance to low ambient light.…”

Влияние Легирования На Свойства Аморфного Гидрогенизированного Кремния, Облученного Фемтосекундными Лазерными Импульсами

“…В частности, имеются данные по влиянию фемтосекундного лазерного облучения пленок a-Si : H на их структуру, содержание водорода, оптическое по-глощение, проводимость и фотопроводимость [16][17][18][19][20][21][22][23][24]. Однако в литературе имеются данные по фемтосекунд-ной лазерной кристаллизации нелегированного a-Si : H. В то же время для создания многих полупроводниковых приборов необходимы элементы как p-, так и n-типа, поэтому интересно рассмотреть влияние легирования на свойства a-Si : H, подвергнутого фемтосекундной лазер-ной кристаллизации.…”