Al1-xSix films were obtained by ion beam sputtering of an Al-Si composite target. Studies of the structure and electronic structure of Al1-xSix films were carried out. The structure and electronic structure of the films were investigated. The formation of an ordered phase of Al3Si was detected using X-ray diffraction and X-ray emission spectroscopy, as well as theoretical calculation of the band structure and Si L2.3-, Al L2.3-spectra. It is established that the Al3Si phase has a Cu3Au (Pm3m) type structure with a lattice parameter a=4.085 angstrom, the primitive sublattices of which are filled with atoms of two types Al and Si. It was found that the long-range order in Al1-xSix ion-beam films is sufficiently resistant to changes in the elemental composition from Al0.75Si0.25 to Al0.55Si0.45.

tangar77@mail.ru Abstract. We present an experimental study of multilayer porous silicon formed by elec-trochemical etching. Special emphasis is placed on effects that arise from a stepwise decrease in the current density while maintaining the total etching time. In order to provide a fully understanding of the morphology of the surface, we used scanning electron and atomic force microscopy. X-ray reflectivity was used to assess the porosity of porous layers. It was found that a stepwise decrease in the current density leads to the formation of a two-layer structure without changing the porosity of the base bottom layer. However, the porosity of the top layer can be varied over a wide range, which directly affects the photoluminescence of the samples. Our results show how the sample production conditions affect the fine tuning of the surface layer morphology of multilayer porous silicon.

X-ray diffraction and scanning electron microscopy data demonstrate that the thermal stability limit of thin PdO films in an oxygen atmosphere rises from 1083 ± 5 to 1133 ± 5 K as the thickness of the starting Pd layers increases from ~10 to ~95 nm, respectively. Unlike the continuous starting metallic palladium layers, the Pd nanostructures resulting from complete thermal decomposition of thin PdO films consist of isolated hemispheric nanocrystallites having well-defined faceting. According to the X-ray diffraction results, the Pd crystallites have (111) and (100) preferential alignment.

Nanocrystalline PdO films have been characterized by X-ray diffraction, scanning electron microscopy, and electron probe microanalysis. The results demonstrate that thermal oxidation in an O2 atmosphere causes ~35-nm-thick nanocrystalline Pd films on SiO2/Si(100) substrates to undergo a sequence of phase transformations resulting in PdO formation, followed by PdO decomposition into metallic Pd at T > 1120 K. In the range 670–970 K, the a and c tetragonal cell parameters of the nanocrystalline PdO films increase monotonically with increasing temperature. The present and previously reported data have been used to construct a model for the unit cell in the crystal structure of palladium(II) oxide. Based on the quasi-chemical approach, we propose a model that accounts for the observed increase in the tetragonal cell parameters and the p-type conductivity of the nanocrystalline PdO films in terms of the formation of excess interstitial oxygen atoms.

The paper presents the results of studies of the structure, electrical and optical properties of ZnO films with Al content from 1 to 5 at.% obtained by the method of ion-beam sputtering of a composite ceramic target in an argon atmosphere. The composite target is a rectangular ZnO ceramic plate with several bands of Al2O3 corundum unevenly distributed over the ZnO surface. In one sputtering cycle, 10 samples were obtained with an aluminum concentration of 1 to 5 at.% as the results of the analysis of the energy dispersion of the second electrons. After deposition, ZnO films were partially crystallized and contained one phase of hexagonal wurtzite with increased parameters a and c. The grain size of the films was estimated using the Scherrer equation and showed a tendency for the grain sizes to change with increasing Al concentration in ZnO films. X-ray diffraction data were confirmed by studying the surface morphology using atomic force microscopy. Measurement of the electrical parameters of the films showed that the smallest resistivity (similar to 4 .10(-3) Ohm . cm) is observed in ZnO films with 1 at.% Al. As the Al concentration in ZnO increases, the resistivity of the films increases, reaching the value rho = 250 Ohm . cm at 5 at.% Al. A possible model of the effect of Al impurity on the electrical properties of ZnO films is considered. Studies of the optical properties of the samples showed that all films are highly transparent (similar to 70 divided by 90%) in the visible light range. The interference bandwidths provide an estimate of the value of the refractive index of ZnO : Al films. From the light absorption spectra, the values of the band gap of ZnO: Al samples were determined and a slight increase in the band gap of ZnO: Al with an increase in the Al concentration in films was established. The mechanism of this behavior of Al impurity in ZnO is discussed. Possible areas of application for ZnO films with Al impurities are considered.

Lead telluride films have been grown on Si (100) and BaF2 (100) substrates by a modified hot-wall method using a graphite reaction chamber. According to X-ray diffraction, X-ray microanalysis, and scanning electron microscopy characterization results, the average growth rate of PbTe films having compositions within the homogeneity range of lead telluride increases with increasing lead vapor partial pressure and decreases with increasing tellurium vapor partial pressure, independent of the nature of the substrate. The rate of PbTe film growth has been shown to be maximal in the initial stage of the process and decrease monotonically over time, independent of the nature of the substrate. Independent of the growth time, the average growth rate of the PbTe films on the Si (100) substrates is considerably higher than that on the BaF2 (100) substrates. Reflection high-energy electron diffraction data indicate that the texture of the PbTe films on Si (100) corresponds to the substrate orientation and that the misorientation angle of the mosaic blocks does not exceed 20°. On the BaF2 (100) substrates, we observe epitaxial PbTe film growth with the orientation relationship (100), [011] PbTe ║ (100), [011] BaF2.

Методами растровой электронной микроскопии, локального рентгеноспектрального анализа, рентгенофазового анализа и атомно-силовой микроскопии изучен количественный элементный состав, фазовая природа, а также морфология поверхности гомогенных пленок теллурида свинца, синтезированных модифицированным методом «горячей стенки» на подложках Si (100). При повышении температуры Si (100) подложки до Т = 593 - 608 К синтезированы мозаичные монокристаллические пленки PdTe с текстурой (100). Установлено, что повышение температуры Si подложки при остальных постоянных режимах синтеза способствует увеличению средних латеральных размеров кристаллитов пленок. Показано, что средняя величина латеральных размеров кристаллитов пленок PbTe на подложках Si (100) увеличивается с ростом толщины и продолжительности синтеза. Установлено, что средние значения шероховатости пленок PbTe/Si (100) увеличиваются с ростом средней толщины пленок PbTe. При этом поликристаллические пленки PbTe/Si (100) при одинаковых значениях средней толщины характеризуются более высокими значениями шероховатости по сравнению с мозаичными монокристаллическими образцами PdTe (100). Экспериментальные исследования были проведены с помощью научно-технической базы ЦКПНО ВГУ.

The paper provides morphological and electro-physical characteristics of the set of structures of the core-shell type of antimony ranging from 10(-4) to 10(-6) m, obtained in a single-stage process as a result of spontaneous crystallization of the melt. It verifies that the structures obtained can be considered as an example of the new type of core-shell structures in a series of self-organized structures derived from their layered precursor. The structures consist of different forms of the same substance, where the core is represented by mono-crystalline gray antimony and the shell is a deformed two-dimensional film. Based on the overall data obtained, the shell of the structure can be described as a cover film with a variable thickness, which contains structural heterogeneities in the form of antimony allotropes, i.e. defective antimonene nano-layers with a high proportion of boundary atoms and dangling bonds. Structural heterogeneity foster electronic effects such as: localized charge contrast, which occurs when an electron beam is applied; emerging of conductive and non-conducting areas on the surface of the shell; electrostatic interaction of particles; ability of the structures to accumulate an excess charge and retain it for a long time. The change in the properties of the nano-shell of the spheroidal structure of the core-shell type of antimony can be considered as a consequence of its deformed structure.

Physics, Chemistry and Applications of Nanostructures, pp. 124-127 (2015) No AccessELECTRONIC AND ATOMIC STRUCTURE OF SILICON NANOCRYSTALS IN ALUMINUM MATRIX AND WITHOUT ITV. A. TEREKHOV, D. S. USOLTSEVA, S. Yu. TURISHCHEV, I. E. ZANIN, B. L. AGAPOV, A. A. LESHOK and P. S. KATSUBAV. A. TEREKHOVVoronezh State University, Universitetskaya 1, 394006 Voronezh, Russia, D. S. USOLTSEVAVoronezh State University, Universitetskaya 1, 394006 Voronezh, Russia, S. Yu. TURISHCHEVVoronezh State University, Universitetskaya 1, 394006 Voronezh, Russia, I. E. ZANINVoronezh State University, Universitetskaya 1, 394006 Voronezh, Russia, B. L. AGAPOVVoronezh State University, Universitetskaya 1, 394006 Voronezh, Russia, A. A. LESHOKBelarusian State University of Informatics and Radioelectronics, P. Browka 6, 220013 Minsk, Belarus and P. S. KATSUBABelarusian State University of Informatics and Radioelectronics, P. Browka 6, 220013 Minsk, Belarushttps://doi.org/10.1142/9789814696524_0032Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: Al–Si nanocomposites have been produced by magnetron sputtering of a compound target onto a silicon substrate. Nanostructured silicon films have further been obtained by selective removal of aluminum. It has been found that silicon particles are nanocrystals with the mean size of 20-25 nm, which surface is covered by an amorphous layer with a thickness of ~5 nm. The band structure (in particular, near the bottom of the valence band) of the nanocomposite films was found to differ from the bulk material because of an influence of the aluminum matrix. After the aluminum removal, the valence band structure becomes identical to that in the bulk material. FiguresReferencesRelatedDetails Physics, Chemistry and Applications of NanostructuresMetrics History PDF download

In the work some peculiarities in formation of the porous silicon, its morphology and composition were investigated, as well as some optical properties of this material. Porous silicon was obtained on the substrates of single-crystalline Si as well as on the silicon structures with p–n junctions. In order to obtain nano-, meso- and macroporous silicon as well as multi-layered porous structures several technological parameters (were controlled) varied—orientation of the substrates, conductivity type and composition of the etchant. Correlation between photoluminescence intensity of the obtained samples and intensity of the absorption band in their IR spectra (the band at 616cm−1) that is due to the presence of Si–Si bonds in porous layer was observed. The influence of the porous silicon storage in the air on the degradation of its photoluminescence parameters was also estimated.

Nanofilms have been grown on InP in the presence of V 2 O 5 introduced into the system by different procedures and methods (within one procedure) and their thickness has been determined by spectral ellipsometry. The phase composition of the films has been determined by X-ray diffraction, and their surface morphology and structure have been analyzed by atomic force microscopy and transmission electron microscopy. The characteristics of the films have been shown to depend on the procedure (through the gas phase in the course of oxidation or by deposition on the surface before oxidation) and method (magnetron sputtering or deposition from gel) used to introduce the chemical stimulator into the system.

Наноразмерные пленки на InP, толщина которых определена методом спектральной эллипсометрии, выращены под воздействием V2O5, введенного в систему различными способами и методами (в рамках одного способа). Фазовый состав установлен рентгенофазовым анализом, морфология поверхности и структура – атомно-силовой и просвечивающей электронной микроскопией. Выявлена зависимость характеристик пленок от способа (через газовую фазу при оксидировании или непосредственное нанесение на поверхность до начала процесса) и метода (магнетронное напыление или осаждение из геля) введения хемостимулятора в систему.

Some features of formation of porous silicon, its morphology and composition, as well as its optical properties were investigated in this work . Porous silicon was obtained on the substrates of single-crystalline Si as well as on the structures with p-n junctions . In order to obtain different structures of nano-, mesoand macroporous silicon as well as multi-layered porous structures several technological parameters were changed — orientation of substrates, conductivity type and composition of the etching solution . Correlation between photoluminescence intensity of the obtained samples and intensity of the absorption band in their IR spectra (the band at 616 cm) that is due to the presence of Si-Si bonds in porous layer . The influence of porous silicon storage in the air on the degradation of photoluminescence parameters of porous silicon was estimated .

Morphology, composition, and optical properties of porous silicon on single-crystal-silicon substrates and p - n junctions are studied. Substrate orientation, type of conduction, and composition of etching agent are varied to obtain nano-, meso-, and microporous silicon and multilayer porous structures. A correlation of the photoluminescence intensity and intensity of the IR absorption band peaking at 616 cm −1 is related to the presence of Si-Si bonds.

The composition and optical properties of composite materials based on porous silicon with iron, cobalt, and nickel deposited by the sol-gel technique are studied. It is shown that the deposition of metal-oxide films onto the surface of porous silicon enables stabilization of the photoluminescence and an increase in its intensity, as well as the storage of hydrogen in the porous layer.

The morphology of the surface of MK-40 and MA-40 ion-exchange membranes in the swollen state after chemical and thermal treatment is studied using scanning electron microscopy. The distribution of portions of the ion exchanger on the surface of heterogeneous membranes is found to be of a complex stochastic nature; their sizes for the MK-40 and MA-40 membranes are 5–30 and 8–40 μm, respectively, while the sizes typical for the secondary porous structure are 2–8 μm. An increase in the share of the ion-exchange component of the surface (by 20–40%), the sizes of the ion-exchange portions (by 20%), and the surface porosity (by two-three times) in the samples subjected to thermal treatment is revealed.