scholarly journals Quality Improvement of Laser-Induced Periodic Ripple Structures on Silicon Using a Bismuth-Indium Alloy Film

2021 ◽  
Vol 11 (2) ◽  
pp. 632
Author(s):  
Yao Chen ◽  
Yao Shan ◽  
Huatian Tu ◽  
Haotian Zhang ◽  
Rong He ◽  
...  
Keyword(s):  
Periodic Structures ◽  
Early Stage ◽  
Alloy Film ◽  
Pulse Number ◽  
Surface Structures ◽  
Large Area ◽  
Free Electrons ◽  
Periodic Surface ◽  
Laser Fluences

In this work, a new buffer layer material, a bismuth-indium (Bi-In) alloy, was utilized to improve the quality of large-area, laser-induced periodic ripple structures on silicon. Better-defined ripple structures and larger modification areas were obtained at different scanning speeds by pre-depositing a Bi-In film. The single-spot investigations indicated that ripple structures were much easier to form on silicon coated with the Bi-In film under laser fluences of 2.04 and 2.55 J/cm2 at a fixed pulse number of 200 in comparison with on bare silicon. A physical model in terms of the excellent thermal conductivity contributed by the free electrons in the Bi-In film homogenizing the thermal distribution caused by the laser irradiation in the early stage of the formation of laser-induced periodic surface structures was proposed to explain the above phenomena. The results show that the Bi-In film enabled a wider range of laser fluences to generate periodic structures and helped to form regular ripple structures on the silicon. In addition, the modulation effects of the laser fluence and pulse number on surface structures were studied experimentally and are discussed in detail.

Large area uniform femtosecond-laser-induced periodic surface structures fabricated on heated LiNbO3:Fe

2021 ◽  
Author(s):  
Yanan Li ◽  
Tianhao Zhang
Keyword(s):  
Femtosecond Laser ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Surface Structures ◽  
Optimum Process ◽  
Large Area ◽  
Periodic Surface ◽  
Laser Fluences ◽  
Fs Laser ◽  
Scanning Irradiation

Abstract The influence of laser fluences and scanning speeds on the morphologies of laser-induced periodic surface structures(LIPSS) on heated LiNbO3:Fe(1000○C) surfaces was investigated under femtosecond(fs) laser scanning irradiation. Laser fluence of 8.5 kJ/m2 and scanning speed of 1 mm/s were found to be optimum process parameters, and large-area fs-LIPSS on LiNbO3:Fe with an area of 8 mm×8 mm were fabricated with these parameters. The wettability of laser-textured LiNbO3:Fe changed to be hydrophilic, and the absorptance was improved substantially in the spectral range of 400-2000 nm. This technique is efficient, and environmentally friendly, which will attract tremendous interest in nano-photoelectron and nano-mechanics.

scholarly journals Large-area fabrication of low- and high-spatial-frequency laser-induced periodic surface structures on carbon fibers

Carbon ◽  
2018 ◽  
Vol 133 ◽  
pp. 176-185 ◽  
Author(s):  
Clemens Kunz ◽  
Tobias N. Büttner ◽  
Björn Naumann ◽  
Anne V. Boehm ◽  
Enrico Gnecco ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Carbon Fibers ◽  
High Spatial Frequency ◽  
Surface Structures ◽  
Large Area ◽  
Periodic Surface ◽  
Frequency Laser

F2-Laser Angle Nanomodification of PET

2007 ◽  
Vol 567-568 ◽  
pp. 257-260
Author(s):  
Petr Slepička ◽  
J. Heitz ◽  
Jakub Siegel ◽  
M. Špírková ◽  
Václav Švorčík
Keyword(s):  
Atomic Force Microscopy ◽  
Laser Irradiation ◽  
Laser Light ◽  
Periodic Structures ◽  
Surface Structures ◽  
Periodic Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Linearly Polarized ◽  
Pet Foils

This work is focused on laser modification of polymers with different angles of incidence. Periodic surface structures generated by linearly polarized F2 laser light (157 nm) on polyethyleneterephthalate (PET) were studied. Atomic force microscopy was used to study the topological changes induced by the laser irradiation. The laser irradiation induces the formation of periodic ripple structures, the width of and the height being angle dependent. The periodic structures were formed with the laser fluence 4.70 mJ/cm2. The laser modified PET foils were coated with a 50 nm thick gold layer by sputtering. After Au deposition on the laser PET foils with ripple structure, the roughness of surface decreases in comparison to PET with ripples without Au coating.

scholarly journals Quasi-periodic Geometry for Architectural Acoustics

2018 ◽  
Vol 15 (1) ◽  
pp. 42-61 ◽  
Author(s):  
Rima Ajlouni
Keyword(s):  
Periodic Structures ◽  
International Standards ◽  
New Wave ◽  
Periodic Surface ◽  
Sound Energy ◽  
New Class ◽  
Quantitative Analyses ◽  
Surface Profiles ◽  
Infinite Variety

The discovery of quasi-periodic atomic order in the crystalline state has uncovered an exciting new class of symmetries that has never been explored before. Because of their non-periodic translational order and self-similar properties, quasi-periodic structures offer unique opportunities for investigating questions related to their acoustical behavior. Their unique long-range non-periodic formations have the ability to diffuse and orchestrate the flow of sound energy in many unique ways; offering intriguing potential for innovating a new wave of optimized sound diffusers. One key limitation with available periodic diffusers is that their repeating logic creates repetitive energy loops, which significantly reduce their ability to uniformly disperse sound energy. Quasi-periodic geometry can mitigate such limitation. By encapsulating an infinite variety of distinct profiles in all directions, quasi-periodic surfaces can eliminate the formation of bundled or looped reflections; considerably enhancing the ability of the diffuser to uniformly disperse sound energy. To investigate this hypothesis, an experimental approach is used to simulate sound reflection patterns of the quasi-periodic surface profiles using a ray tracing method. Both qualitative and quantitative analyses are used to interpret the simulated results. The international Standards (ISO) metrics are used to validate the proposed approach and verify the results. Results show that the diffusion quality of the tested quasi-periodic surface is superior to the diffusion performance of the tested periodic surface.

scholarly journals A microscope image processing method for analyzing TLIPSS structures

2019 ◽  
Vol 43 (6) ◽  
pp. 936-945
Author(s):  
D.A. Belousov ◽  
A.V. Dostovalov ◽  
V.P. Korolkov ◽  
S.L. Mikerin
Keyword(s):  
Periodic Structures ◽  
Scanning Speed ◽  
Processing Method ◽  
Surface Structures ◽  
Beam Power ◽  
Relative Area ◽  
Gaussian Laser Beam ◽  
Periodic Surface ◽  
Writing Beam ◽  
Chromium Films

The paper describes a method for processing microimages of thermochemical laser-induced periodic surface structures (TLIPSS) to quantify their structural order and defects. Results of its application for the analysis of microimages of periodic structures formed in 30-nm chromium films by an astigmatically focused femtosecond Gaussian laser beam have been presented. Dependences of the relative area of the beam-modified region, the area of defects, and the ordering of the periodic structures on the scanning speed and the writing beam power have been obtained.

scholarly journals Thermochemical Laser-Induced Periodic Surface Structures Formation by Femtosecond Laser on Hf Thin Films in Air and Vacuum

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6714
Author(s):  
Dmitrij A. Belousov ◽  
Kirill A. Bronnikov ◽  
Konstantin A. Okotrub ◽  
Sergey L. Mikerin ◽  
Victor P. Korolkov ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Orientation Angle ◽  
Ambient Air ◽  
Chemical Oxidation ◽  
Surface Structures ◽  
Large Area ◽  
Temperature Oxidation ◽  
Periodic Surface ◽  
High Regularity ◽  
Wide Range

Thermochemical laser-induced periodic surface structures (TLIPSS) are a relatively new type of periodic structures formed in the focal area of linear polarized laser radiation by the thermally stimulated reaction of oxidation. The high regularity of the structures and the possibility of forming high-ordered structures over a large area open up possibilities for the practical application for changing the optical and physical properties of materials surface. Since the mechanism of formation of these structures is based on a chemical oxidation reaction, an intriguing question involves the influence of air pressure on the quality of structure formation. This paper presents the results on the TLIPSS formation on a thin hafnium film with fs IR laser radiation at various ambient air pressures from 4 Torr to 760 Torr. Despite the decrease in the oxygen content in the ambient environment by two orders of magnitude, the formation of high-ordered TLIPSS (dispersion in the LIPSS orientation angle δθ < 5°) with a period of ≈700 nm occurs within a wide range of parameters variation (laser power, scanning speed). This behavior of TLIPSS formation is in agreement with experimental data obtained earlier on the study of the kinetics of high-temperature oxidation of hafnium at various oxygen pressures.

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