Femtosecond pulse crystallization of thin amorphous hydrogenated films on glass substrates using near ultraviolet laser radiation

Володин, В. А.; Kachko, Alexandr; Черков, А. Г.; Латышев, А. В.; Koch, Jürgen; Chichkov, Boris N.

doi:10.1134/s0021364011100134

Cited by 13 publications

(6 citation statements)

References 17 publications

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“…The presence of a wide band with a maximum at ω A = 480 cm −1 , which is characteristic to amorphous silicon, can be seen in Raman spectra of all the samples in Figure 3 a. Along with it, a narrow line near ω C = 520 cm −1 , which corresponds to crystalline (nanocrystalline) silicon (nc-Si) [ 4 , 29 ], is present only in the irradiated samples.…”

Section: Resultsmentioning

confidence: 96%

“…The crystalline silicon (c-Si) phase volume fraction f C in the irradiated films was calculated using the following expression [ 29 ]:

where I A and I C are the integrated intensities of TO phonon modes corresponding to the frequencies ω A and ω C , σ 0 is the empirical ratio of the Raman scattering integrated cross sections for the crystalline and amorphous silicon phases, which is determined by the formed silicon nanocrystals size [ 30 ]. The size of nanocrystals estimated from the shift of the Raman line at 520 cm −1 [ 30 ] is ≈3.6 nm for sample 2 and ≈5 nm for sample 1.…”

Section: Resultsmentioning

confidence: 99%

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Fabricating Femtosecond Laser-Induced Periodic Surface Structures with Electrophysical Anisotropy on Amorphous Silicon

et al. 2020

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One-dimensional periodic surface structures were formed by femtosecond laser irradiation of amorphous hydrogenated silicon (a-Si:H) films. The a-Si:H laser processing conditions influence on the periodic relief formation as well as correlation of irradiated surfaces structural properties with their electrophysical properties were investigated. The surface structures with the period of 0.88 and 1.12 μm were fabricated at the laser wavelength of 1.25 μm and laser pulse number of 30 and 750, respectively. The orientation of the surface structure is defined by the laser polarization and depends on the concentration of nonequilibrium carriers excited by the femtosecond laser pulses in the near-surface region of the film, which affects a mode of the excited surface electromagnetic wave which is responsible for the periodic relief formation. Femtosecond laser irradiation increases the a-Si:H films conductivity by 3 to 4 orders of magnitude, up to 1.2 × 10−5 S∙cm, due to formation of Si nanocrystalline phase with the volume fraction from 17 to 28%. Dark conductivity and photoconductivity anisotropy, observed in the irradiated a-Si:H films is explained by a depolarizing effect inside periodic microscale relief, nonuniform crystalline Si phase distribution, as well as different carrier mobility and lifetime in plane of the studied samples along and perpendicular to the laser-induced periodic surface structures orientation, that was confirmed by the measured photoconductivity and absorption coefficient spectra.

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Section: Resultsmentioning

confidence: 96%

“…The crystalline silicon (c-Si) phase volume fraction f C in the irradiated films was calculated using the following expression [ 29 ]:

Section: Resultsmentioning

confidence: 99%

Fabricating Femtosecond Laser-Induced Periodic Surface Structures with Electrophysical Anisotropy on Amorphous Silicon

et al. 2020

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“…The nanocrystalline phase volume fraction f C in the irradiated films can be calculated from the Raman spectra using the expression [ 4 , 41 ]:

where I A and I C are the integral intensities of the TO phonon modes corresponding to lines near the frequencies ω A and ω C in the Raman spectrum, and σ 0 is the empirical ratio of the Raman-scattering integral cross sections for the nc-Si and a-Si phases, which is determined by the size of the formed silicon nanocrystals according to the formula [ 4 , 42 ]: σ 0 = 0.1 + exp(− d nc-Si /25). …”

Section: Resultsmentioning

confidence: 99%

Femtosecond Laser Fabrication of Anisotropic Structures in Phosphorus- and Boron-Doped Amorphous Silicon Films

et al. 2022

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Femtosecond laser-modified amorphous silicon (a-Si) films with optical and electrical anisotropy have perspective polarization-sensitive applications in optics, photovoltaics, and sensors. We demonstrate the formation of one-dimensional femtosecond laser-induced periodic surface structures (LIPSS) on the surface of phosphorus- (n-a-Si) and boron-doped (p-a-Si) amorphous silicon films. The LIPSS are orthogonal to the laser polarization, and their period decreases from 1.1 ± 0.1 µm to 0.84 ± 0.07 µm for p-a-Si and from 1.06 ± 0.03 to 0.98 ± 0.01 for n-a-Si when the number of laser pulses per unit area increases from 30 to 120. Raman spectra analysis indicates nonuniform nanocrystallization of the irradiated films, with the nanocrystalline Si phase volume fraction decreasing with depth from ~80 to ~40% for p-a-Si and from ~20 to ~10% for n-a-Si. LIPSS’ depolarizing effect, excessive ablation of the film between LIPSS ridges, as well as anisotropic crystalline phase distribution within the film lead to the emergence of conductivity anisotropy of up to 1 order for irradiated films. Current–voltage characteristic nonlinearity observed for modified p-a-Si samples may be associated with the presence of both the crystalline and amorphous phases, resulting in the formation of potential barriers for the in-plane carrier transport and Schottky barriers at the electric contacts.

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“…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.…”

Section: (поступила в редакцию 13 февраля 2017 г)unclassified

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

Денисова¹,

Ильин²,

Мартышов³

et al. 2018

Физика Твердого Тела

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A comparative analysis of the effect of femtosecond laser irradiation on the structure and conductivity of undoped and boron-doped hydrogenated amorphous silicon ( a -Si: H) is performed. It is demonstrated that the process of nanocrystal formation in the amorphous matrix under femtosecond laser irradiation is initiated at lower laser energy densities in undoped a -Si: H samples. The differences in conductivity between undoped and doped a -Si: H samples vanish almost completely after irradiation with an energy density of 150–160 mJ/cm^2.

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Femtosecond pulse crystallization of thin amorphous hydrogenated films on glass substrates using near ultraviolet laser radiation

Cited by 13 publications

References 17 publications

Fabricating Femtosecond Laser-Induced Periodic Surface Structures with Electrophysical Anisotropy on Amorphous Silicon

Fabricating Femtosecond Laser-Induced Periodic Surface Structures with Electrophysical Anisotropy on Amorphous Silicon

Femtosecond Laser Fabrication of Anisotropic Structures in Phosphorus- and Boron-Doped Amorphous Silicon Films

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

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