Belarusian State University of Informatics and Radioelectronics

About: Belarusian State University of Informatics and Radioelectronics is a education organization based out in Minsk, Belarus. It is known for research contribution in the topics: Silicon & Thin film. The organization has 1089 authors who have published 1329 publications receiving 9241 citations. The organization is also known as: Minsk Radio Engineering Institute.

Electronic Properties of Bulk and Monolayer TMDs: Theoretical Study Within DFT Framework (GVJ-2e Method)

Abstract: Accurate prediction of band gap for new emerging materials is highly desirable for the exploration of potential applications. The band gaps of bulk and monolayer TMDs (MoS2, MoSe2, WS2, and WSe2) are calculated with the recently proposed by us GVJ-2e method, which is implemented within DFT framework without adjustable parameters and is based on the total energies only. The calculated band gaps are in very good agreement with experimental ones for both bulk and monolayer TMDs. For monolayer MoS2, MoSe2, WS2, and WSe2, direct band gaps are predicted to be 1.88 eV, 1.57 eV, 2.03 eV, 1.67 eV correspondingly, and for bulk TMDs, indirect band gaps of 1.23 eV (MoS2), 1.09 eV (MoSe2), 1.32 eV (WS2), 1.21 eV (WSe2) are predicted. The GVJ-2e method demonstrates good accuracy with mean absolute error (MAE) of about 0.03 eV for TMDs PL gaps (and 0.06 eV for QP gaps). GVJ-2e method allows to equally accurately obtain band gaps for 3D and 2D materials. The errors of GVJ-2e method are significantly smaller than errors of other widely used methods such as GW (MAE 0.23 eV), hybrid functional HSE (MAE 0.17 eV), TB-mBJ functional (MAE 0.14 eV).

Photonic band gap phenomenon and optical properties of artificial opals

Abstract: We report on the photonic band gap phenomenon in the visible range in a three-dimensional dielectric lattice formed by close-packed spherical silica clusters. The spectral position and the spectral width of the optical stop band depend on the direction of light propagation with respect to the crystal axes of opal, and on the relative cluster-to-cavity refraction index n. Manifestations of the photonic pseudogap have been established for both transmission and emission spectra. The stop band peak wavelength shows a linear dependence on n. Transmission characteristics of the lattice have been successfully simulated by numerical calculations within the framework of a quasicrystalline approximation. @S1063-651X~97!13805-3#

Isostructural BaSi2, BaGe2 and SrGe2: electronic and optical properties

Abstract: We have performed a theoretical study of the electronic band structure, density of states, dielectric function and absorption coefficient of isostructural BaSi2, BaGe2 and SrGe2 compounds by means of different ab initio methods. All materials are found to be indirect band-gap semiconductors displaying almost equal dispersion of bands close to the gap region. The energy gaps of 0.83, 0.57 and 0.44 eV are estimated for BaSi2, BaGe2 and SrGe2, respectively. Analysis of the absorption coefficient of BaSi2 in comparison with data for other semiconducting silicides indicates its prospects for a solar cell application. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Superconducting MgB2 thin films on silicon carbide substrates by hybrid physical–chemical vapor deposition

Abstract: We have used two polytypes of silicon carbide single crystals, 4H-SiC and 6H-SiC, as the substrates for MgB2 thin films grown by hybrid physical-chemical vapor deposition (HPCVD). The c-cut surface of both polytypes has a hexagonal lattice that matches closely with that of MgB2. Thermodynamic calculations indicate that SiC is chemically stable under the in situ deposition conditions for MgB2 using HPCVD. The MgB2 films on both polytypes show high-quality epitaxy with a Rutherford backscattering channeling yield of 12%. They have Tc above 40 K, low resistivities, high residual resistivity ratios, and high critical current densities. The results demonstrate that SiC is an ideal substrate for MgB2 thin films.

Ab initio modeling of the structural, electronic, and optical properties of A II B IV C 2 V semiconductors

Abstract: The structural, electronic, and optical properties of II--IV--V${}_{2}$ (II $=$ Be, Mg, Zn, Cd; IV $=$ Si, Ge, Sn; V $=$ P, As) chalcopyrite-type ternaries have been theoretically investigated from first principles. The compounds demonstrate semiconducting behavior, with the direct-band gap ranging from about 0.2 to 2.2 eV, except for Be-containing materials, which indicate an indirect gap. The band gaps in II--IV--P${}_{2}$ are always larger than corresponding ones in II--IV--As${}_{2}$. All compounds are characterized by similar optical spectra with some anisotropy effects. MgGeAs${}_{2}$, MgSnP${}_{2}$, MgSnAs${}_{2}$, ZnSiAs${}_{2}$, ZnGeP${}_{2}$, ZnSnP${}_{2}$, CdSiAs${}_{2}$, and CdGeP${}_{2}$ were found to have the dipole matrix element of the first direct transition comparable with one for GaAs, that may be useful in light-emitting structures. ZnSiAs${}_{2}$, ZnSnAs${}_{2}$, and their solid solutions seem to be the most promising candidates for photovoltaic applications because of their reflectance and absorption spectra.