3C-SiC epitaxial layers with a thickness of up to 100 μm were grown on 6H-SiC hexagonal substrates by sublimation epitaxy in vacuum. The n-type epitaxial layers with the area in the range 0.3-0.5 cm2 and uncompensated donor concentration N d - N a ∼ (10 17-1018) cm-3 were produced at maximum growth rates of up to 200 μm/h. An X-ray analysis demonstrated that the epitaxial layers are composed of the 3C-SiC polytype, without inclusions of other polytypes. The photoluminescence (PL) spectrum of the layers was found to be dominated by the donor-acceptor (Al-N) recombination band peaked at hv ≈ 2.12 eV. The PL spectrum measured at 6 K was analyzed in detail. It is concluded that the epitaxial layers obtained can serve as substrates for 3C-SiC-based electronic devices. © Nauka/Interperiodica 2007.

Within the frame of a simple model, based on Hertz-Knudsen equation with account of temperature dependant sticking coefficient, temperature dependence of silicon carbide epitaxial layers growth rate in vacuum has been calculated. Calculation results are in a good agreement with the experimental data.

Exciton spin relaxation in diluted magnetic semiconductor (DMS) structures based on ZnMnSe is closely examined as a function of exciton spin splitting in an external magnetic field. A drastic increase in spin relaxation is observed when exciton spin splitting exceeds the longitudinal optical (LO) phonon energy. Direct experimental evidence has been provided from (1) spin injection from the DMS to an adjacent nonmagnetic quantum well that can be modulated by the LO-assisted spin relaxation and (2) hot exciton photoluminescence within the DMS where a spin flip is accompanied by the emission of one LO phonon.

GaN/AlGaN quantum wells (QWs) of dominant N polarity with inversion domains (IDs), grown by molecular-beam epitaxy, have been studied. Two-band photoluminescence (PL), with the lower-energy band and an additional absorption edge related to the IDs, is observed in these QWs due to a difference in strain, electric field, and well width in the regions of different polarities. A time-resolved PL study reveals additionally strong inhomogeneity of the electric fields among the IDs. The intrinsic electric fields in the structures are relatively small-their maximal estimated value of 180 kV/cm is among the lowest ever reported. The low-scale electric fields indicate likely polarization deterioration in the N-polarity structures. These conditions are favorable for bright PL up to room temperature in 8-9-nm-wide wells.

The characteristics of boron incorporation and the resultant electrical behaviour have been studied for sublimation grown epilayers. Some factors which influence are the purity of the source material, growth temperature and growth time. The electrical activity of the shallow and deep level of boron has been investigated in relation to growth parameters and from the results the nature of the deep boron complex is discussed. The use of TaC coated graphite crucibles resulted in a decrease of the Z(1,2) concentration to less than low E13 cm(-3) which is the concentration obtained using graphite crucibles.

The signal value of the transistor-like detector on applied voltage was investigated. It was measure induced-current recording from fluxes of X-ray and optical quanta. A superlinear rise in the resulting signal was observed with increasing voltage. The signal was amplified by a factor of several tens with respect to the value chosen for normalization. A description in terms of the phototriode model gives acceptable values for the main parameters: base width, diffusion length of electrons, and space charge region of the collector. It is important that SiC films with the thickness d similar to 10 mum can be used to detect penetrating radiation, for example, X-ray. The effective thickness of the films exceeds d by the signal amplification factor (and proves to be in range of hundred mum).

The aim of this study was an estimation of the radiation hardness of silicon carbide and devices on its base. By using data, obtained by the authors, and literature data, it was possible to calculate carrier removal rate in SiC, irradiated by different charge participles, radiation defects (RD) introduction rate and generation constant of deeper RD. The obtained results were compared with known values of this parameters for Si. Results of comparison show, that during calculation of above parameters for SiC (or other wide-bandgap semiconductors (WBS), it is necessary to take into account their temperature dependence. Commonly, this comparison shows, that SiC is perspective material for developing radiation resistive devices, especially if they must work at high temperatures.

We report on optical and structural studies of the interface symmetry in CdSe/BeTe multiple-layer structures containing self-assembled quantum dots. Temperature and decay behavior of the broad photoluminescence (PL) band is consistent with the type-II transitions involving deeply localized electron states. Large linear in-plane polarization of the PL (up to 80%) is observed, implying the C-2v (or lower) symmetry of the individual places of the electron localization.