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Information × Registration Number 0223U005475, 0123U102709 , R & D reports Title Optically and acoustically controlled devices based on crystalline and nanocomposite materials for modulation of terahertz radiation popup.stage_title Head Andrushchak Anatolii S., Доктор технічних наук Registration Date 22-12-2023 Organization Lviv Polytechnic National University popup.description2 The main objectives of this stage of work were the selection and manufacture of the necessary samples of crystalline materials and nanoporous matrices, modernization of experimental equipment, measurement of the necessary parameters of crystalline samples and nanoporous matrices, as well as research on the photogeneration of carriers in the selected materials. To implement the project, the necessary equipment and crystal samples of Si, Ge, Bi12GeO20 (BGO), Bi12SiO20 (BSO), as well as samples of Se thin films on a quartz substrate, nanoporous matrices of various structures and geometries from Si and SiO2 were purchased. The electrical conductivity of samples of Si, Ge, BGO, BSO and thin films, as well as the nanoporous Al2O3 matrix was measured. Electrical conductivity measurements were carried out by impedance spectroscopy methods, as well as by the four-probe Van der Pauw method. Impedance measurements in the frequency range from 10-2 to 10 6 Hz indicated the contribution of various mechanisms to the resulting electrical conductivity. Spectral studies of bulk and thin-film materials, as well as nanoporous matrices have been carried out. The dependences of the transmission and reflection spectra were analyzed, the thicknesses of thin films, the optical constants of the materials were determined, and the band gaps of the investigated materials were determined. A stand was manufactured to measure the effect of illuminaton on the carrier generation in the selected materials. The carrier photogeneration in Si crystals under different experimental conditions was studied. On the basis of experimental data, changes in conductivity and carrier concentration depending on the power of the incident radiation were determined. In Ge crystals, the study of carrier photogeneration is hindered by the high absorption of light radiation (for λ ≤ 550 nm). High values of dark resistances were found in BGO, BSO crystals and Se films.  Product Description popup.authors Andrushchak Nazariy Balaban Oksana Bendak Andriy Venhryn Bohdan Danylov Andriy Shchur Yaroslav popup.nrat_date 2023-12-22 Close