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6Highly regular nanogratings on metal and amorphous semiconductor thin films: diversity of formation mechanisms,
properties and applications
K. Bronnikov12, V. Terentiev2, V. Simonov2, V. Fedyaj23, S. Babin23, A. Zhizhchenko4, A. Kuchmizhak45, A. Dostovalov2*
1- School of Physics and Engineering, ITMO University, 191002 St. Petersburg, Russia 2- Institute of Automation and Electrometry of the SB RAS, 1 Acad. Koptyug Ave., 630090 Novosibirsk, Russia 3- Novosibirsk State University, 630090 Novosibirsk, Russia 4- Institute of Automation and Control Processes of the FEB RAS, 5 Radio St., 690041 Vladivostok, Russia 5- Far Eastern Federal University, 690041 Vladivostok, Russia
During the last decades, the phenomenon of laser-induced periodic surface structures (LIPSS) formation under the impact of laser radiation with high intensity has been extensively studied in case of nearly all types of materials [1]. Due to a vacuum-free, single step and low-cost approach with a possibility to control structures morphology and optical properties, surface nanostructuring based on LIPSS has already found the applications in photonics, biomedicine, tribology and sensing. Recently, a new type of LIPSS called "thermochemical LIPSS" (TLIPSS) was discovered as a result of laser-driven chemical reaction of oxidation on the surface of titanium thin films [2]. The outstanding regularity of the structures obtained in the ablation-free process on a large scale stimulated the further research in this area.
In this work we review our recent results on TLIPSS formation in the case of femtosecond laser radiation impact on thin metal films of Ti, Hf, Al and Cr, as well as amorphous thin films of semiconductors (Si and Ge). In particular, sub-wavelength (A/1.5) periodic surface structures were obtained on the mentioned above metal thin films in a broad range of experimental parameters (pulse energy, processing speed) possessing high regularity of the structures (deviation of angle orientation DLOA<2°) with a throughput up to 0.2 mm2/s [3]. The influence of ambient atmosphere on a chemical reaction of oxidation and hence the morphology of obtained structures was also investigated [4]. In the case of amorphous semiconductors thin films, the new regimes of TLIPSS formation accompanied by laser-induced crystallization process in the case of Si [5] and oxide sublimation in the case of Ge thin films were revealed [6].
Moreover, the results of creation of structures with 2D periodicity in the different strategies of surface processing are shown. More specifically, regular square and hexagonal 2D structures depending on processing parameters were produced on Ti thin films providing the way for diffractive optical elements inscription based on this approach.
The work was supported by the Russian Science Foundation grant (No. 21-72-20162). In the research, we used the equipment of the following Multiple-Access Centres (MAC): MAC of the Far Eastern Federal University (FEFU), MAC "High-resolution spectroscopy of gases and condensed matters" at IAE SB RAS, MAC of the Novosibirsk State University (NSU).
[1] J. Bonse, et al, Handbook of Laser Micro- and Nano-Engineering (Springer International Publishing), Laser-Induced Periodic Surface Structures (LIPSS), (2020).
[2] B. Oktem, et al, Nonlinear laser lithography for indefinitely large-area nanostructuring with femtosecond pulses, Nature Photonics, 7, 897-901 (2013).
[3] D. A. Belousov, et al, Thermochemical Laser-Induced Periodic Surface Structures Formation by Femtosecond Laser on Hf Thin Films in Air and Vacuum, Materials, 14, 6714 (2021).
[4] K. Bronnikov, et al, Regulating Morphology and Composition of Laser-Induced Periodic Structures on Titanium Films with Femtosecond Laser Wavelength and Ambient Environment, Nanomaterials 12, 306 (2022).
[5] A. Dostovalov, et al, Hierarchical anti-reflective laser-induced periodic surface structures (LIPSSs) on amorphous Si films for sensing applications, Nanoscale 12, 13431-13441 (2020).
[6] K. Bronnikov, et al, Highly regular nanogratings on amorphous Ge films via laser-induced periodic surface sublimation, Optics & Laser Technology 169, 110049 (2024).
