The paper presents the acoustoelectric phenomenon in a layered structure: piezoelectric waveguide – semiconductor. The publication presents an original acoustic method for determining the electrical and electron parameters of the subsurface area in crystalline semiconductors. The method is based on the so-called transverse acoustoelectric effect realized in a layer system: piezoelectric waveguide with Rayleigh surface acoustic wave – semiconductor. The paper discusses the physical foundations of the transverse acoustoelectric effect in the piezoelectric – semiconductor layer system, taking into account the distinctness of the physical properties of the semiconductor near-surface region in relation to its volumetric properties. The work covers many experimental studies of the near-surface region of semiconductors. The original method was presented to determine such surface parameters as: surface potential, surface conductivity, mobility of carriers in the subsurface area, life time of charge carriers in surface states. By means of the acoustic method the following semiconductors have been extensively tested: indium phosphide InP and gallium phosphide GaP. These semiconductors are one of the main semiconductors of group III-V, which are the basis of modern photonics, optoelectronics as well as integrated optics. The work also includes an analysis of the measurement possibilities of the developed acoustic method and its limitations, as well as an analysis of the accuracy of the obtained values of the parameters of the subsurface area of crystalline semiconductors.

The electronic, magnetic, and optical properties of PtCoBi half-Heusler compound [001] surfaces and its bulk state have been investigated in the framework of density functional theory using GGA approximation. The half-metallic behaviors of CoBi-term, CoPt-term and PtBi-term decrease with respect to its bulk state. The spin polarization at the Fermi level is 73.2% for the bulk state, and it is –64.4% and –64.1% for the CoBi-term and PtBi-term, respectively while less polarization has been observed for the ­CoPt-term. All terminations have given almost similar optical responses to light. Plasmon oscillations for the terminations occur in the range of 12.5 to 14.5 eV (21 to 22 eV) along xx (zz), and it occurs at 23 eV for the bulk state. The refractive index for the bulk and all three terminations is very high in the infrared and visible areas, meaning a very strong metallic trend in these compounds. The phenomenon of super-luminance occurs for the incident light with energy exceeding 5.5 eV for all three terminations, and it occurs in the range of 10 eV for the bulk mode. These terminations show transparent behavior after the energy of 10 eV.

Mechanical, electronic, thermodynamic phase diagram and optical properties of the FeVSb half-Heusler have been studied based on the density functional theory (DFT) framework. Studies have shown that this structure in the MgAgAs-type phase has static and dynamic mechanical stability with high thermodynamic phase consistency. Electronic calculations showed that this compound is a p-type semiconductor with an indirect energy gap of 0.39 eV. This compound’s optical response occurs in the infrared, visible regions, and at higher energies its dielectric sign is negative. The Plasmon oscillations have occurred in 20 eV, and its refraction index shifts to zero in 18 eV.

The effects of hydrogen absorption and manganese substitution on structural, electronic, optical, and thermoelectric properties of silicon-carbon nanotubes (SiCNT) are studied using the density functional theory and the GGA approximation. An examination of the PDOS curves and the electronic band structure showed that the Mn substitution leads to an increase in magnetic anisotropy and the occurrence of semi-metallic behavior and that the hydrogen absorption shifts the band gap toward the lower energies. A study of these nanostructures’ thermoelectric behavior reveals that the H absorption leads to a significant escalation in the figure of merit of the SiCNT to about 1.6 in the room temperature range. The effects of the H absorption on this nanotube’s optical properties, including the dielectric functions and its absorption spectra, are also investigated.

The electronic, optical and thermoelectric properties of MoS2 nano-sheet in presence of the Ru impurity have been calculated by density functional theory framework with Generalized Gradient approximation. The MoRuS2 nano-sheet electronic structure was changed to the n-type semiconductor by 1.3 eV energy gap. The optical coefficients were shown that the loosing optical energy occurred in the higher ultraviolet region, so this compound is a promising candidate for optical sensing in the infrared and visible range. The thermoelectric behaviors were implied to the good merit parameter in the 100K range and room temperatures and also has high amount of power factor in 600K which made it for power generators applications.

In this paper, structural, electronic, thermal, and thermoelectric properties of Al _0.25B _0.75As alloy, under pressures 0 GPa, 4 GPa and 8 GPa, have been calculated. The value of band gap at present work under 0 GPa, with GGA(PBE) exchange-correlation potential, is very close to other works with TB-mBJ method. This is a result of equal selection of muffin-tin radius spheres that are bigger than usual size for Al and B atoms. The values of band gap decrease by increasing pressure. In thermal properties, phonon contribution of heat capacity at constant volume and Debye temperature have been calculated in the range of 0K to 1000K temperatures and under 0 GPa, 4 GPa and 8 GPa pressures. Thermoelectric properties, under the same pressures and in the range of 100K to 1000K temperatures have been investigated.

In this article, synthesis, electronic and optical properties of an N-cyclohexyl-acrylamide (NCA) molecule are described based on different solvent environments and supported by theoretical calculations. Theoretical calculations have been carried out using a density function theory (DFT). Temperature dependence of the sample electrical resistance has been obtained by a four-point probe technique. Experimental and semi-theoretical parameters such as optical density, transmittance, optical band gap, refractive index of the NCA for different solvents were obtained. Both optical values and electrical resistance values have shown that NCA is a semiconductor material. The values of HOMO and LUMO energy levels of the headline molecule indicate that it can be used as the electron transfer material in OLEDs. All results obtained confirm that the NCA is a candidate molecule for OLED and optoelectronic applications.