Femtosecond Laser-Induced Simultaneous Surface Texturing and Crystallization of a-Si:H Thin Film: Absorption and Crystallinity

Hydrogenated amorphous silicon (a-Si:H) thin films have been considered for use in solar cell applications because of their significantly reduced cost. Their overall efficiency and stability, however, are less than that of their bulk crystalline counterparts. Limited work has been performed on solving the efficiency and stability issues of a-Si:H simultaneously. In this study, both surface texturing and crystallization on a-Si:H thin film are achieved through one-step femtosecond laser processing. The nanoscale conical and pillar-shaped spikes formed on the surface of a-Si:H films by femtosecond laser irradiation in both air and water are presented and enhanced light absorption is observed due to light trapping based on surface geometry changes, while the formation of a mixture of hydrogenated nanocrystalline silicon (nc-Si:H) and a-Si:H after crystallization suggests that the overall material stability can potentially be increased. The relationship among crystallinity, fluence, and scan speed is also discussed. Furthermore, a comparison of absorptance spectra for various surface morphologies is developed. Finally, the absorptance measurement across the solar spectrum shows that the combination of surface texturing and crystallization induced by femtosecond laser processing is very promising for a-Si:H thin film solar cell applications.

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Femtosecond Laser-Induced Surface Texturing and Crystallization of a-Si:H Thin Film

ASME 2010 International Manufacturing Science and Engineering Conference, Volume 2 ◽

10.1115/msec2010-34271 ◽

2010 ◽

Cited By ~ 1

Author(s):

Hongliang Wang ◽

Panjawat Kongsuwan ◽

Gen Satoh ◽

Y. Lawrence Yao

Keyword(s):

Thin Film ◽

Solar Cell ◽

Femtosecond Laser ◽

Laser Processing ◽

Light Trapping ◽

Surface Texturing ◽

Surface Geometry ◽

Femtosecond Laser Processing ◽

Stability Issues ◽

Surface Morphologies

Hydrogenated amorphous silicon (a-Si:H) thin films have been considered for use in solar cell applications because of their significantly reduced cost, however, the overall efficiency and stability are less than that of their bulk crystalline counterparts. Limited work has been performed on solving the efficiency and stability issues of a-Si:H simultaneously. In this study, both surface texturing and crystallization on a-Si:H thin film are achieved through one-step femtosecond laser processing in water. Light absorption is enhanced by light trapping based on surface geometry changes, and the formation of a mixture of hydrogenated microcrystalline silicon (μc-Si:H) and a-Si:H after crystallization suggests that the overall stability may be increased. Furthermore, the formation mechanism for the surface spikes is discussed. A comparison of absorptance spectra for various surface morphologies and crystallinities shows that the combination of surface texturing and crystallization induced by femtosecond laser processing is very promising for a-Si:H thin film solar cell applications.

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Interfering Ultraviolet Femtosecond Laser Processing of Gold Thin Film and Prospect of Shortest Period

Applied Physics Express ◽

10.1143/apex.5.102703 ◽

2012 ◽

Vol 5 (10) ◽

pp. 102703 ◽

Cited By ~ 5

Author(s):

Yoshiki Nakata ◽

Keiichi Murakawa ◽

Noriaki Miyanaga ◽

Kazuma Momoo

Keyword(s):

Thin Film ◽

Femtosecond Laser ◽

Laser Processing ◽

Gold Thin Film ◽

Femtosecond Laser Processing

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femtosecond laser processing for a thin film coated transparent target

The Proceedings of The Manufacturing & Machine Tool Conference ◽

10.1299/jsmemmt.2019.13.b12 ◽

2019 ◽

Vol 2019.13 (0) ◽

pp. B12

Author(s):

Yuki HIROTSU ◽

Terutake HAYASHI ◽

Syuhei KUROKAWA ◽

Ryosuke MIZUMACHI ◽

Noboru HASEGAWA ◽

...

Keyword(s):

Thin Film ◽

Femtosecond Laser ◽

Laser Processing ◽

Femtosecond Laser Processing

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Impact of femtosecond laser processing on dielectric layers for solar cell applications

Journal of Laser Applications ◽

10.2351/1.5028314 ◽

2018 ◽

Vol 30 (3) ◽

pp. 032019

Author(s):

Jaffar Moideen Yacob Ali ◽

Vinodh Shanmugam ◽

Carlos D. Rodríguez-Gallegos ◽

Armin G. Aberle ◽

Thomas Mueller

Keyword(s):

Solar Cell ◽

Femtosecond Laser ◽

Laser Processing ◽

Dielectric Layers ◽

Femtosecond Laser Processing

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Generation of complicated or duplicated structure by interfering femtosecond laser processing of metallic thin film

10.1117/12.874407 ◽

2011 ◽

Author(s):

T. Hiromoto ◽

K. Momoo ◽

Y. Nakata ◽

N. Miyanaga

Keyword(s):

Thin Film ◽

Femtosecond Laser ◽

Laser Processing ◽

Femtosecond Laser Processing ◽

Metallic Thin Film

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Study on femtosecond laser processing with photo excitation for a thin film coated transparent target

The Proceedings of Conference of Kyushu Branch ◽

10.1299/jsmekyushu.2019.72.c41 ◽

2019 ◽

Vol 2019.72 (0) ◽

pp. C41

Author(s):

Yuki HIROTSU ◽

Terutake HAYASHI ◽

Syuhei KUROKAWA ◽

Ryosuke MIZUMACHI

Keyword(s):

Thin Film ◽

Femtosecond Laser ◽

Laser Processing ◽

Femtosecond Laser Processing

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Generation of New Nanomaterials by Interfering Femtosecond Laser Processing

MRS Proceedings ◽

10.1557/proc-850-mm1.4 ◽

2004 ◽

Vol 850 ◽

Cited By ~ 1

Author(s):

Yoshiki Nakata ◽

Okada Tatsuo

Keyword(s):

Thin Film ◽

Femtosecond Laser ◽

Laser Fluence ◽

Laser Processing ◽

The Other ◽

Laser Beams ◽

Nanohole Array ◽

Silica Substrate ◽

Femtosecond Laser Processing ◽

Layered Thin Film

ABSTRACTNew nanomaterials such as nanobump array, nanomesh, nanobelt were generated from thin film processed by interfering femtosecond laser beams. Metallic single- or multi-layered film deposited on a silica substrate was used as a raw thin film. With four interfering femtosecond laser beams, a conical nanobump arrayed in a matrix was generated with single laser shot. As the femtosecond laser fluence increased, the nanobump increased in diameter and height, and a bead was found at the top. Moreover, with three or two interfering femtosecond laser beams, ellipsoidal or linear nanobump array was generated. As an application of a conical nanobump array, field emission from the nanobump array was demonstrated, and the I-V characteristics were measured. On the other hand, with much higher fluence and four interfering femtosecond laser beams, a nanohole array was generated. A nanomesh was also generated from the nanohole array by exfoliating the film. A grating was generated with two interfering femtosecond laser beams, and nanobelts were generated from the grating by exfoliating. Bimetallic nanobelt was also generated from multi-layered thin film.

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An Ab Initio Molecular Dynamics Simulation of Femtosecond Laser Processing of Germanium

ASME 2013 4th International Conference on Micro/Nanoscale Heat and Mass Transfer ◽

10.1115/mnhmt2013-22161 ◽

2013 ◽

Author(s):

Pengfei Ji ◽

Yuwen Zhang

Keyword(s):

Molecular Dynamics ◽

Femtosecond Laser ◽

Ab Initio ◽

Laser Processing ◽

Density Functional ◽

Dynamic Properties ◽

Dynamics Simulation ◽

Femtosecond Laser Irradiation ◽

Ab Initio Molecular Dynamics ◽

Femtosecond Laser Processing

An ab initio molecular dynamics study of femtosecond laser processing of germanium is presented in this paper. The method based on the finite temperature density functional theory is adopted to probe the nanostructure change, thermal motion of the atoms, dynamic property of the velocity autocorrelation, and the vibrational density of states. Starting from a cubic system at room temperature (300 K) containing 64 germanium atoms with an ordered arrangement of 1.132 nm in each dimension, the femtosecond laser processing is simulated by imposing the Nose Hoover thermostat to the electron subsystem lasting for ∼100 fs and continuing with microcanonical ensemble simulation of ∼200 fs. The simulation results show solid, liquid and gas phases of germanium under adjusted intensities of the femtosecond laser irradiation. We find the irradiated germanium distinguishes from the usual germanium crystal by analyzing their melting and dynamic properties.

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