TY - JOUR

T1 - Highly regular nanogratings on amorphous Ge films via laser-induced periodic surface sublimation

AU - Bronnikov, K.

AU - Gladkikh, S.

AU - Mitsai, E.

AU - Modin, E.

AU - Zhizhchenko, A.

AU - Babin, S.

AU - Kuchmizhak, A.

AU - Dostovalov, A.

N1 - 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).

PY - 2024/2

Y1 - 2024/2

N2 - Despite the fact that monocrystalline germanium (Ge) was historically the first material where formation of laser-induced periodic surface structures (LIPSSs) was observed in 1965 and then extensively studied, practically relevant thin films of amorphous Ge (a-Ge) were occasionally ignored by these studies so far. Here, highly regular LIPSSs were observed on the surface of magnetron-sputtered a-Ge films under near-IR femtosecond laser exposure. Formation of these regular structures was explained by excitation and interference of the surface waves at the interface of photoexcited Ge that was confirmed by performed calculations and full-wave simulations. At the same time, remarkable structural regularity of these LIPSSs unveiled their ablation-free formation scenario involving laser-driven oxidation of the Ge followed by ultra-clean sublimation of the oxide. Laser patterning in vacuum was found to regulate oxidation/sublimation rates of the a-Ge and its oxide improving the structure quality and opening pathways for practical applications in optoelectronics, solar light harvesting and near-IR photonics.

AB - Despite the fact that monocrystalline germanium (Ge) was historically the first material where formation of laser-induced periodic surface structures (LIPSSs) was observed in 1965 and then extensively studied, practically relevant thin films of amorphous Ge (a-Ge) were occasionally ignored by these studies so far. Here, highly regular LIPSSs were observed on the surface of magnetron-sputtered a-Ge films under near-IR femtosecond laser exposure. Formation of these regular structures was explained by excitation and interference of the surface waves at the interface of photoexcited Ge that was confirmed by performed calculations and full-wave simulations. At the same time, remarkable structural regularity of these LIPSSs unveiled their ablation-free formation scenario involving laser-driven oxidation of the Ge followed by ultra-clean sublimation of the oxide. Laser patterning in vacuum was found to regulate oxidation/sublimation rates of the a-Ge and its oxide improving the structure quality and opening pathways for practical applications in optoelectronics, solar light harvesting and near-IR photonics.

KW - Femtosecond laser pulses

KW - Laser-induced periodic surface structures

KW - Surface plasmons

KW - a-Ge films

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85171162336&origin=inward&txGid=165d9471bfcec4d334d513cb6b3f30bd

UR - https://www.mendeley.com/catalogue/db717294-ef65-3cbf-8a54-72cdd7d6650e/

U2 - 10.1016/j.optlastec.2023.110049

DO - 10.1016/j.optlastec.2023.110049

M3 - Article

VL - 169

JO - Optics and Laser Technology

JF - Optics and Laser Technology

SN - 0030-3992

M1 - 110049

ER -