Search academic texts

Information × Registration Number 0224U031512, 0122U001956 , R & D reports Title Nanostructured metasurfaces for sensors and photovoltaics popup.stage_title Head Dmytruk Ihor M., Доктор фізико-математичних наук Registration Date 03-05-2024 Organization Taras Shevchenko National University of Kyiv popup.description2  Laser-induced periodic surface structures (LIPSS) have been formed on metal surfaces (Ag, Mo, Cu, W) and on metal films on semiconductors (Au-Si, Au-GaAs) under irradiation by femtosecond laser with a wavelength of 800 or 1300 nm. LIPSS replicas have been obtained by mechanical pressing on Cu and Ag foils using Mo and W molds with LIPSS on the surfaces. As a result of pressing, quasi-periodic structures are obtained on the surfaces of Cu and Ag foils. Surface structures before and after pressing have been investigated using scanning electron and atomic force microscopes. Both types of periodic surface structures were used for surface-enhanced Raman spectroscopy (SERS). Test measurements have been performed for Rhodamine 6G dye on smooth and structured surfaces. High SERS enhancement coefficients have been obtained also for vibrational modes of the nucleotide 5'-deoxyadenosine monophosphate (dAMP) on two types of metasurfaces: LIPSS on silver with triangular silver nanoprisms and LIPSS on silicon crystal with a thin gold film, which was modified by the treatment with femtosecond laser radiation. A gain of 117 times compared to a smooth silver surface have been achieved. The use of LIPSS on noble metals and more complex metasurfaces with LIPSS and noble metal nanoparticles makes it possible to increase significantly the sensitivity of sensors that work on the SERS effect to detect certain chemicals, for example, biological, poisonous or explosive. A new method of monitoring of the process of laser surface structuring has been developed, which is based on the registration of the spectra of secondary emission during the structuring process. According to the results of the study of its polarization and kinetics, 3 types of secondary emission have been identified: the generation of the second harmonic of the laser (400 nm), the lines of atomic silicon, which evaporates during the structuring process, and the bands of SiN molecules. Product Description popup.authors Yeshchenko Oleh А. Bediukh Oleksаndr R. Berezovska Nataliia I. Hrabovskyi Evhen S. Mamykin Serhii V. Pundyk Iryna P. Stanovyi Oleksandr P. Tomchuk Anastasiia V. Khort Pavlo S. popup.nrat_date 2024-05-03 Close