Denys Ihorovych Kurbatov

MORFOLOGICAL AND STRUCTURAL CHARACTERISTICS OF II–VI SEMICONDUCTOR THIN FILMS (ZnTe, CdTe, ZnS)

ABSTRACT The surface morphology and microstructural characteristic of ZnTe, CdTe and ZnS thin films obtained by close-spaced sublimation technique were investigated. The structural features of layers were examined by XRD, SEM and optical microscopy. Size of coherent scattering regions, lattice microstrain and stacking fault defect concentration were estimated from X-ray diffraction line broadening. The investigation performed elucidates effect of preparation conditions on main structural characteristics of ZnTe, CdTe and ZnS thin films.

Characteristics of structure formation in zinc and cadmium chalcogenide films deposited on nonorienting substrates

The phase composition, texture quality, size of coherent scattering domains, microstrain level, and concentration of stacking faults in zinc and cadmium chalcogenide (ZnS, ZnSe, ZnTe, CdSe, CdTe) films deposited by close-spaced vacuum sublimation method on nonorienting substrates have been investigated. The analysis was performed by X-ray diffraction. The substructural characteristics were determined from the physical broadening of diffraction lines using the Hall method and threefold convolution. The dependence of the structural properties of chalcogenide films on the deposition conditions are characterized.

Injection and Optical Spectroscopy of Localized States in II-VI Semiconductor Films

Novel achievements of nanoand microelectronics are closely connected with working-out of new semiconductor materials. Among them the compounds II-VI (where A = Cd, Zn, Hg and B = О, S, Se, Te) are of special interest. Due to unique physical properties these materials are applicable for design of optical, acoustical, electronic, optoelectronic and nuclear and other devices [1-3]. First of all the chalcogenide compounds are direct gap semiconductors where the gap value belongs to interval from 0.01 eV (mercury chalcogenides) up to 3.72 eV (ZnS with zinc blende crystalline structure) As potential active elements of optoelectronics they allow overlapping the spectral range from 0.3 m to tens m if using them as photodetectors and sources of coherent and incoherent light. The crystalline structure of IIVI compounds is cubic and hexagonal without the center of symmetry is a good condition for appearing strong piezoeffect. Crystals with the hexagonal structure have also pyroelectric properties. This feature may be used for designing acoustoelectronic devices, amplifiers, active delay lines, detectors, tensile sensors, etc. [1-2]. Large density of some semiconductors (CdTe, ZnTe, CdSe) makes them suitable for detectors of hard radiation and –particles flow [4-5]. The mutual solubility is also important property of these materials. Their solid solutions give possibility to design new structures with in-advance defined gap value and parameters of the crystalline lattice, transmission region, etc. [6].

Morphology, chemical composition and optical properties of Cu2ZnSnSe4 nanoparticles synthesized by colloidal method

The present paper concerns the studies of the peculiarities of morphology, elemental composition and optical properties of semiconductor nanoparticles Cu2ZnSnSe4 synthesized by a colloidal method by transmission electron microscopy, energy dispersive X-ray and optical spectroscopy.

Raman analysis of Zn1-xMnxTe polycrystalline films

In this paper, we have investigated some structural properties, Raman spectra of Zn1-xMnxTe films deposited by the closed space vacuum sublimation under different growth conditions. The obtained results of the Raman spectroscopy and XRD analysis show single phase composition of the samples. The presence of phonon replicas in the Raman spectra of the films indicates their high structural quality. The manganese content (about 7 %) in the layers was determined according to shifting the relative peaks positions.

Thermoelectric Properties of the Colloidal Bi2S3-Based Nanocomposites

In this work we present the proof of the concept of the novel strategy to improve the thermoelectric properties of Bi2S3 based nanostructured bulk materials by blending the metallic nanoinclusions with the semiconductor nanoparticles forming the nanocomposites (NCts). The obtained NCts were composed of Bi2S3 nanorods (length – 100 nm and width – 10 nm) and Ag nanoparticles (diameter – 2-3 nm) synthesized by the colloidal method. The morphology, phase and chemical composition, electrical conductivity and Seebeck coefficient of NCts were investigated by using transmission electron microscopy (TEM), X-ray diffraction, energy dispersive X-ray analysis (EDAX), 4-point probes method and static dc-method. This strategy is the perspective way to improve the conversion efficiency of others thermoelectric materials.

Investigation of optical properties of magnesium oxide films obtained by spray pyrolysis technique

Today more and more areas of optoelectronics used oxide materials, as a result, their study, is very important. Therefore, in this paper, we study optical properties of magnesium oxide films.

Structural characteristics of Zn1-xMnxTe polycrystalline films

Manganese-doped A2(1-x)MnxB6 diluted magnetic semiconductors have recently attracted a great attention as a new class of semiconductors, because they exhibit an interesting combination of magnetic and semiconductor properties. Zn1-xMnxTe films were deposited by the closed space vacuum sublimation method on the glass substrates. Particle induced X-ray emission method was applied for determination of the film chemical composition. Structural investigations of the films were performed using X-ray diffractometer with CuKα radiation. The obtained results enabled to determine the effect of the growth conditions on the main structural parameters (lattice parameters, SDS, microdeformation levels) and chemical compositions of the films.

Optical properties of II-Mn-VI films obtained by close-spaced vacuum sublimation technique

Optical properties of Zn<inf>1−x</inf>Mn<inf>x</inf>S and Cd<inf>1−x</inf>Mn<inf>x</inf>Te films, obtained by close-spaced vacuum sublimation technique are investigated. Measuring of optical characteristics layers was carried out by spectrophotometric analysis. This research allowed to obtained spectral distributions of transmittance, reflectance and absorption coefficients of films and to expect band-gap energy of materials.