Search academic texts

Information × Registration Number 0224U033022, (0124U004077) , R & D reports Title Physical and chemical aspects of formation of low-dimensional structures in Ag–As–Sb–S system for functional electronics popup.stage_title Виконання комплексу робіт з отримання склоподібних і кристалічних матеріалів Ag–As–Sb–S та проведення фізичних досліджень Head Gomonnai Oleksandr V., Доктор фізико-математичних наук Registration Date 16-12-2024 Organization Institute of Electronic Physics of the National Academy of Sciences of Ukraine popup.description1 The aim of the project is to elucidate the conditions of formation of semiconductor nanocrystals in glassy and thin-film materials of Ag–As–Sb–S system and to determine the possibilities of their parameters to be modified by fabrication regimes and laser irradiation, to study specific features of photostructural and photochemical effects in heterophase composites as well as electrical and optical characteristics of single-crystal, amorphous, and composite materials of the Ag–As–Sb–S system popup.description2 The project is focused on physical and chemical aspects of fabrication of composites with semiconductor nanocrystals in glassy and thin-film Ag–As–Sb–S materials and modification of their parameters by technological regimes and external factors. Due to the improvement of technological processes (As2S3)1-xAgx glasses with 0.01 ≤ x ≤ 0.2 are obtained and their physical properties are studied. With increasing Ag content in the Agx(As2S3)1-x glasses the optical band gap and the single oscillator energy decrease, while the dispersion energy increases and the bond ionicity degree is practically unchanged. Photooxidation of As2S3:Ag glass (x  0.04) under visible light (532 nm, 40 kW/cm2) is revealed by Raman spectroscopy where As2O3-related peaks emerge in the spectra. Photooxidation is facilitated by the presence of Ag in the glass structure, reducing its rigidity, or possible enhancement of the photochemical reaction due to plasmonic interaction of the incident light with residual ultrasmall Ag nanoparticles in the glass sample. Introduction of Ag into Sb2S3 results in a polycrystalline two-phase alloy Sb2S3–AgSbS2 confirmed by X-ray diffraction, energy-dispersive spectroscopic analysis and a slight transformation of the absorption edge compared to Sb2S3. Ag3AsS3.and Ag3SbS3 single crystals were grown by directed crystallisation and studied by Raman spectroscopy and spectroellipsometry, their refractive index dispersion was determined. Ag3As0.8Sb0.2S3 single crystal was grown, its structural and ellipsometric studies were performed. Using density functional theory for the description of Ag3AsS3-type crystals, a combination of the DFT/GGA approach with dispersion correction results in the optimal results compared to the experiment, the deviation from the determined Ag3AsS3 lattice parameter not exceeding 3%. The most accurate data, in particular, bandgap energy 2.08 eV, are obtained using the Hubbard parameter simultaneously for the d-orbitals of Ag and p-orbitals of S. Product Description popup.authors Azhniuk Yurii M. Babuka Tetiana Ya. Voinarovych Ivan M. Kryshenyk Volodymyr M. Lopushanskyi Vasyl V. Pohodin Artem I. popup.nrat_date 2024-12-16 Close