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12 pages, 1878 KiB

Open AccessArticle

Highly Regular LIPSS on Thin Molybdenum Films: Optimization and Generic Criteria

by Juraj Sládek, Kryštof Hlinomaz, Inam Mirza, Yoann Levy, Thibault J.-Y. Derrien, Martin Cimrman, Siva S. Nagisetty, Jan Čermák, The Ha Stuchlíková, Jiří Stuchlík and Nadezhda M. Bulgakova

Materials 2023, 16(7), 2883; https://doi.org/10.3390/ma16072883 - 4 Apr 2023

Cited by 8 | Viewed by 2412

Abstract

A systematic experimental study was performed to determine laser irradiation conditions for the large-area fabrication of highly regular laser-induced periodic surface structures (HR-LIPSS) on a 220 nm thick Mo film deposited on fused silica. The LIPSS were fabricated by scanning a linearly polarized, spatially Gaussian laser beam at 1030 nm wavelength and 1.4 ps pulse duration over the sample surface at 1 kHz repetition rate. Scanning electron microscope images of the produced structures were analyzed using the criterion of the dispersion of the LIPSS orientation angle (DLOA). Favorable conditions, in terms of laser fluence and beam scanning overlaps, were identified for achieving DLOA values <10

^{\circ}

. To gain insight into the material behavior under these irradiation conditions, a theoretical analysis of the film heating was performed, and surface plasmon polariton excitation is discussed. A possible effect of the film dewetting from the dielectric substrate is deliberated. Full article

(This article belongs to the Special Issue Advances in Laser Materials and Processing Technologies)

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10 pages, 3412 KiB

Open AccessArticle

Nanoscale Soft Wetting Observed in Co/Sapphire during Pulsed Laser Irradiation

by Jung Won Choi, Daseul Ham, Seonghyun Han, Do Young Noh and Hyon Chol Kang

Nanomaterials 2021, 11(2), 268; https://doi.org/10.3390/nano11020268 - 20 Jan 2021

Cited by 2 | Viewed by 2264

Abstract

Liquid drops on deformable soft substrates exhibit quite complicated wetting behavior as compared to those on rigid solid substrates. We report on a soft wetting behavior of Co nanoparticles (NPs) on a sapphire substrate during pulsed laser-induced dewetting (PLID). Co NPs produced by PLID wetted the sapphire substrate with a contact angle near 70°, which is in contrast to typical dewetting behavior of metal thin films exhibiting contact angles greater than 90°. In addition, a nanoscale γ-Al₂O₃ wetting ridge about 15 nm in size and a thin amorphous Al₂O₃ interlayer were observed around and beneath the Co NP, respectively. The observed soft wetting behavior strongly indicates that the sapphire substrate became soft and deformable during PLID. Moreover, the soft wetting was augmented under PLID in air due to the formation of a CoO shell, resulting in a smaller contact angle near 30°. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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13 pages, 4096 KiB

Open AccessArticle

Antifungal Properties of Pure Silver Films with Nanoparticles Induced by Pulsed-Laser Dewetting Process

by Ying-Hong Lin, Jyun-Jhih Wang, Yung-Ting Wang, Hsuan-Kai Lin and Yi-Jia Lin

Appl. Sci. 2020, 10(7), 2260; https://doi.org/10.3390/app10072260 - 26 Mar 2020

Cited by 15 | Viewed by 3580

Abstract

Silver particles were prepared by dewetting Ag films coated on glass using a fiber laser. The size of the particles was controlled in the range of 92 nm–1.2 μm by adjusting the thickness of the Ag film. The structural properties and surface roughness of the particles were evaluated by means of scanning electron microscopy. In addition, the antifungal activity of the Ag particles was examined using spore suspensions of Colletotrichum gloeosporioides. It is shown that particles with a size of 1.2 μm achieved 100% inhibition of conidia growth of C. gloeosporioides after a contact time of just 5 min. Furthermore, the smaller particles also achieved good antifungal activity given a longer contact time. Similar results were observed for spore germination and pathogenicity tests performed on mango fruit and leaves. Overall, the results confirm that Ag particles have an excellent antifungal effect on C. gloeosporioides. Full article

(This article belongs to the Special Issue Advances in Surface Modification of the Materials)

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3 pages, 410 KiB

Open AccessProceeding Paper

Graphene Paper-Gold Nanostructured Electrodes Obtained by Laser Dewetting for High Sensitive Non-Enzymatic Glucose Sensing

by Antonino Scandurra, Francesco Ruffino and Maria Grazia Grimaldi

Proceedings 2019, 15(1), 1; https://doi.org/10.3390/proceedings2019015001 - 19 Jun 2019

Viewed by 1700

Abstract

Electrodes for non-enzymatic glucose sensing based on gold nanostructures onto graphene paper (GP-AuNPs) have been obtained inducing dewetting, by laser annealing, of 8 nm-thick Au layer deposited by sputtering. Molten-phase dewetting of gold layer, which produces the formation of spherical nanoparticles (AuNPs), was achieved by nanosecond laser annealing using a pulsed (12 ns) Nd: yttrium aluminum garnet YAG laser operating at 532 nm. The Surface of the electrode presents gold rich regions consisting of graphene nanoplatelets covered by spherical AuNPs. The sizes of AuNPs are in the range of 10–150 nm. Glucose was detected at a potential of 0.17 V vs SCE, which corresponds to the intense peak of two electrons oxidation. Highest sensitivity of 600 µA mM⁻¹ cm⁻² of glucose detection was obtained. The resulting sensitivity, detection limit and linear range of glucose detection are very promising since comparable to the actual state of art results for nanostructured gold electrodes which are, however, produced by complex multi-steps processes. Full article

(This article belongs to the Proceedings of 7th International Symposium on Sensor Science)

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