scholarly journals Structural Rearrangement of a-SiOx:H Films with Pulse Photon Annealing

Author(s):  
Vladimir A. Terekhov ◽  
Evgeny I. Terukov ◽  
Yury K. Undalov ◽  
Konstantin A. Barkov ◽  
Igor E. Zanin ◽  
...  

Amorphous SiOx films with silicon nanoclusters are a new interesting material from the standpoint of the physics, technology, and possible practical applications, since such films can exhibit photoluminescence due to size quantization. Moreover, the optical properties of these structures can be controlled by varying the size and the content of silicon nanoclusters in the SiOx film, as well as by transforming nanoclusters into nanocrystals by means of high-temperature annealing. However, during the annealing of nonstoichiometric silicon oxide, significant changes can occur in the phase composition and the structure of the films. The results of investigations on the crystallization of silicon nanoclusters in a SiOx matrix have shownthat, even a very fast method of annealing using PPA leads to the formation of large silicon crystallites. This also causes the crystallization of at least a part of the oxide phase in the form of silicon hydroxide H6O7Si2. Moreover, in films with an initial content of pure silicon nanoclusters ≤ 50%, during annealing a part of the silicon is spent on the formation of oxide, and part of it is spent on the formation of silicon crystals. While in a film with an initial concentration of silicon nanoclusters ≥ 53%, on the contrary, upon annealing, there occurs a partial transition of silicon from the oxide phase to the growth ofSi crystals        Reference 1. Undalov Y. K., Terukov E. I., Silicon nanoclustersncl-Si in a hydrogenated amorphous silicon suboxidematrix a-SiOx:H (0 < x < 2). Semiconductors. 2015;49(7):867- 878. DOI: https://doi.org/10.1134/S10637826150702222. Kim K. H., Johnson E. V., Kazanskii A. G.,Khenkin M. V., Roca P. Unravelling a simple methodfor the low temperature synthesis of siliconnanocrystals and monolithic nanocrystalline thinfilms. Scientific Reports. 2017;7(1) DOI: https://doi.org/10.1038/srep405533. Undalov Y. K., Terukov E. I., Trapeznikova I. N.Formation of ncl-Si in the amorphous matrix a-SiOx-:H located near the anode and on the cathode, usinga time-modulated DC plasma with the (SiH4–Ar–O2)gas phase (Co2 = 21.5 mol%). Semiconductors.2019;53(11): 1514–1523. DOI: https://doi.org/10.1134/S10637826191102284. Terekhov V. A., Terukov E. I., Undalov Y. K.,Parinova E. V., Spirin D. E., Seredin P. V., Minakov D. A.,Domashevskaya E. P. Composition and optical propertiesof amorphous a-SiOx:H films with silicon nanoclusters.Semiconductors. 2016;50(2): 212–216. DOI:https://doi.org/10.1134/S10637826160202515. Terekhov V. A., Turishchev S. Y., Kashkarov V. M.,Domashevskaya E. P., Mikhailov A. N., Tetel’baum D. I.Silicon nanocrystals in SiO2 matrix obtained by ionimplantation under cyclic dose accumulation. PhysicaE: Low-dimensional Systems and Nanostructures.2007;38(1-2): 16–20. DOI: https://doi.org/10.1016/j.physe.2006.12.0306. Terekhov V. A., Turishchev S. Y., Pankov K. N.,Zanin I. E., Domashevskaya E. P., Tetelbaum D. I.,Mikhailov A. N., Belov A. I., Nikolichev D. E., Zubkov S. Y.XANES, USXES and XPS investigations of electronenergy and atomic structure peculiarities of the siliconsuboxide thin film surface layers containing Si nanocrystals.Surface and Interface Analysis. 2010;42(6-7):891–896. DOI: https://doi.org/10.1002/sia.33387. Terekhov V. A., Turishchev S. Y., Pankov K. N.,Zanin I. E., Domashevskaya E. P., Tetelbaum, MikhailovA. N., Belov A. I., Nikolichev D. E. Synchrotron investigationsof electronic and atomic-structure peculiaritiesfor silicon-oxide films’ surface layers containingsilicon nanocrystals. Journal of Surface Investigation.X-ray, Synchrotron and Neutron Techniques. 2011;5(5):958–967. DOI: https://doi.org/10.1134/S102745101110020X8. Sato K., Izumi T., Iwase M., Show Y., Morisaki H.,Yaguchi T., Kamino T. Nucleation and growth of nanocrystallinesilicon studied by TEM, XPS and ESR.Applied Surface Science. 2003;216 (1-4): 376–381. DOI:https://doi.org/10.1016/S0169-4332(03)00445-89. Ledoux G., Gong J., Huisken F., Guillois O., ReynaudC. Photoluminescence of size-separated siliconnanocrystals: Confirmation of quantum confinement.Applied Physics Letters. 2002;80(25): 4834–4836. DOI:https://doi.org/10.1063/1.148530210. Patrone L., Nelson D., Safarov V. I., Sentis M.,Marine W., Giorgio S. Photoluminescence of siliconnanoclusters with reduced size dispersion producedby laser ablation. Journal of Applied Physics. 2000;87(8):3829–3837. DOI: https://doi.org/10.1063/1.37242111. Takeoka S., Fujii M., Hayashi S. Size-dependentphotoluminescence from surface-oxidized Si nanocrystalsin a weak confinement regime. Physical ReviewB. 2000;62(24): 16820–16825. DOI: https://doi.org/10.1103/PhysRevB.62.1682012. Ievlev V. M. Activation of solid-phase processesby radiation of gas-discharge lamps, Russian ChemicalReviews. 2013;82(9): 815–834. DOI: https://doi.org/10.1070/rc2013v082n09abeh00435713. Zimkina T. M., Fomichev V. A. Ultrasoft X-Rayspectroscopy. Leningrad: Leningrad State UniversityPubl.; 1971. 132 p.14. Wiech G., Feldhütter H. O., Šimůnek A. Electronicstructure of amorphous SiOx:H alloy filmsstudied by X-ray emission spectroscopy: Si K, Si L, andO K emission bands. Physical Review B. 1993;47(12):6981–6989. DOI: https://doi.org/10.1103/Phys-RevB.47.698115. Domashevskaya E. P., Peshkov Y. A., TerekhovV. A., Yurakov Y. A., Barkov K. A., Phase compositionof the buried silicon interlayers in the amorph o u s m u l t i l a y e r n a n o s t r u c t u r e s[(Co45Fe45Zr10)/a-Si:H]41 and [(Co45Fe45Zr10)35(Al2O3)65/a-Si:H]41. Surface and Interface Analysis.2018;50(12-13): 1265–1270. DOI: https://doi.org/10.1002/sia.651516. Terekhov V. A., Kashkarov V. M., ManukovskiiE. Yu., Schukarev A. V., Domashevskaya E. P.Determination of the phase composition of surfacelayers of porous silicon by ultrasoft X-ray spectroscopyand X-ray photoelectron spectroscopy techniques.Journal of Electron Spectroscopy and Related Phenomena.2001;114–116: 895–900. DOI: https://doi.org/10.1016/S0368-2048(00)00393-517. JCPDS-International Centre for DiffractionData ICDD PDF-2, (n.d.) card No 01-077-2110.18. JCPDS-International Centre for DiffractionData ICDD PDF-2, (n.d.) card No 00-050-0438.

Author(s):  
Muhkametkali Mataev ◽  
Moldir Abdraimova ◽  
A. Atabay

The complex oxide phase of the composition YbBiNaFe2O6,5 was synthesized by the high-temperature solid-phase reaction. X-ray diffraction analysis was used to study the structure for the first time; the type of syngony, unit cell parameters, X-ray diffraction and pycnometric densities were determined. X-ray diffraction was carried out by homology method from the initial fluorite structure δBi2O3. The method of least squares refined the parameters of the crystal lattice. The parameters of the orthorhombic lattice of complex mixed ferrite at the value of the number of formula units Z=4 are: a=5.2319, в=5.2186, с=7.5702 Å. The correctness of the results of the X-ray diffraction of complex mixed ferrite was confirmed by the good agreement between the experimental and calculated values of the inverse squares of the interplanar distances (104/d2). Satisfactory consistency of the values of the X-ray and pycnometric densities, ρrad = 8.335, ρpik = 8.328 g/cm3, proves the correctness of the results of the experiment. A comparative analysis of the interrelation between the parameters of the crystal lattice and the parameters of the crystal lattices of the initial oxide δBi2O3. The analysis shows the values of the parameters “a” and “c” are in satisfactory agreement with the parameters of the crystal lattice δBi2O3, the parameter “c” is distorted from the value of the parameter “a” on √2.


2021 ◽  
Vol 2124 (1) ◽  
pp. 012016
Author(s):  
I Goncharov ◽  
M Kovaleva ◽  
M Yapryntsev ◽  
V Sirota

Abstract In this article, new composite coatings ZrB2-35MoSi2-15Al were deposited on the surface of a carbon-carbon composite using a multi-chamber detonation accelerator. The evolution of the phase composition of ZrB2-35MoSi2-15Al coatings was analyzed with differential scanning calorimeter (DSC) and X-ray diffractometry (in situ HT-XRD) at temperatures from room temperature (∼ 25°C) to 1400°C (normal atmosphere and pressure). The coating before annealing according to X-ray diffractometry data is tetragonal (t-ZrO2) and monocline (m-ZrO2) zirconium dioxide, monocline silicon oxide (m-SiO2), hexagonal zirconium diboride (h-ZrB2), tetragonal molybdenum disilicide (t-MoSi2), cubic aluminum (c-Al) and cubic yttrium oxide (c-Y2O3). It was found that the coating crystallizes in m-ZrO2 at 460ºC, and then mullite with rhombic crystal lattice appears at 960ºC. When the temperature reaches 1050ºC the m-ZrO2, ZrSiO4, t-ZrO2, m-SiO2 and mullite phases formed in the coating. At 1400 º C, cubic zirconium dioxide appears in the coating. Experimental results can become the basis for the application of ceramic coating ZrB2-35MoSi2-15Al, which can improve the properties of carbon-carbon composites in an oxygen-containing environment at elevated temperatures.


Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1515
Author(s):  
Halyna Klym ◽  
Ivan Karbovnyk ◽  
Andriy Luchechko ◽  
Yuriy Kostiv ◽  
Viktorija Pankratova ◽  
...  

BaGa2O4 ceramics doped with Eu3+ ions (1, 3 and 4 mol.%) were obtained by solid-phase sintering. The phase composition and microstructural features of ceramics were investigated using X-ray diffraction and scanning electron microscopy in comparison with energy-dispersive methods. Here, it is shown that undoped and Eu3+-doped BaGa2O4 ceramics are characterized by a developed structure of grains, grain boundaries and pores. Additional phases are mainly localized near grain boundaries creating additional defects. The evolution of defect-related extended free volumes in BaGa2O4 ceramics due to the increase in the content of Eu3+ ions was studied using the positron annihilation lifetime spectroscopy technique. It is established that the increase in the number of Eu3+ ions in the basic BaGa2O4 matrix leads to the agglomeration of free-volume defects with their subsequent fragmentation. The presence of Eu3+ ions results in the expansion of nanosized pores and an increase in their number with their future fragmentation.


Author(s):  
V. G. Shmorgun ◽  
A. I. Bogdanov ◽  
O. V. Slautin ◽  
V. P. Kulevich

The phase composition of the oxide films on the surface of the Fe-Cr-Al system coatings is studied using glancing angle X-ray diffraction. It is shown that at 900 °С the formed oxide films consist of αAlO and (FeCr)O, to which FeAlO oxide is added during long-term exposure. An increase in temperature to 1100 °C intensifies the growth of oxide films, and an increase in the aluminum content ensures a stable growth of αAlO and FeAlO oxides. When the aluminum content in the coating is more than 10 at. % at large exposure times, metastable alumina δAlO is formed, the formation of which is associated with a decrease in the concentration of chromium in thin surface layers.


2019 ◽  
Vol 970 ◽  
pp. 250-256
Author(s):  
Evgeniy Nikolaev ◽  
Elena Lysenko ◽  
Anatoly P. Surzhikov

The effect of complex high-energy action, including mechanical milling of Li2CO3-Fe2O3-ZnO initial reagents mixture and its consistent heating by the pulsed electron beam on solid-phase synthesis was studied by X-ray powder diffraction and thermal analyses. The initial mixture Li2CO3-Fe2O3-ZnO corresponds to the ferrite with stoichiometric formula: Li0.5(1–x)ZnxFe2.5–0.5xО4, where х = 0.2. The same studies were carried out with thermal heating in a laboratory furnace for detection the effect of radiation on the formation of phase composition lithium-zinc ferrite. Initial mixture was milled in AGO-2S planetary ball mill with a milling speed of 2220 rpm for 60 min. Radiation-thermal synthesis of the milled mixture was carried out by the pulsed electron accelerator (ILU-6) at 600°C and 750°C. The maximum time of the isothermal stage was 60 minutes. According to the X-ray powder diffraction and thermogravimetric analysis, it was found that the complex high-energy action leads to decrease a temperature and time of obtaining lithium-zinc ferrite homogeneous in phase composition. The proposed high-energy regimes allow to synthesized lithium-zinc ferrites at 600 °C for 60 minutes, which is much lower compared to conventional ceramic technology.


2011 ◽  
Vol 29 (1) ◽  
pp. 134-144 ◽  
Author(s):  
Vishal Koradia ◽  
Mikko Tenho ◽  
Heidi Lopez de Diego ◽  
Michiel Ringkjøbing-Elema ◽  
Jørn Møller-Sonnergaard ◽  
...  

1997 ◽  
Vol 51 (12) ◽  
pp. 1781-1783 ◽  
Author(s):  
D. L. Perry ◽  
A. C. Thompson ◽  
R. E. Russo ◽  
X. L. Mao ◽  
K. L. Chapman

A synchrotron X-ray fluorescence microprobe has been used to study the composition and microstructure of pulsed-laser ablation-deposited films of calcium–nickel–potassium oxides that have applications in heterogeneous catalysis. The films, whose individual metal oxide components have widely varying boiling points and thus prevent a solid-phase synthesis with the use of standard thermal techniques, represent a new quaternary metal oxide phase containing the three elements. Experimental conditions for preparing the films are given. The X-ray fluorescence microprobe data are discussed with respect to both the distribution of the three metals in the films at the micrometer lateral spatial resolution level and the presence of trace amounts of metals that were introduced into the films as contaminants in targets made of the parent three-metal oxide.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5209
Author(s):  
Sergei Galyshev ◽  
Evgeniya Postnova ◽  
Olga Shakhlevich ◽  
Dmitrii Agarkov ◽  
Ekaterina Agarkova ◽  
...  

This work is devoted to the study of the chemical and phase composition of a carbon fiber coating obtained by the electrochemical sol-gel method. The experimental data obtained using several independent complementary methods, including X-ray phase analysis, thermogravimetric and differential thermal analysis, scanning electron microscopy and elemental analysis, and X-ray photoelectron spectroscopy, are in good agreement with each other. It was found that the resulting coating consists of amorphous silicon oxide and crystalline potassium carbonate. Heating above 870 °C leads to the crystallization of cristobalite from amorphous silicon dioxide. At a temperature of about 870 °C, the coating acquires a smooth surface, and heating above 1170 °C leads to its destruction. Thus, the optimum temperature for the heat treatment of the coating is about 870 °C. The loss of strength of carbon fiber at each stage of coating was estimated. A full coating cycle, including thermal cleaning from the sizing, coating, and heat treatment, results in a loss of fiber strength by only 11% compared to the initial state.


2012 ◽  
Vol 452-453 ◽  
pp. 77-80 ◽  
Author(s):  
Shou Jun Wu ◽  
Gutmanas Elazar

In order to improve oxidation/erosion resistance of the T/P 24 steel components used in advanced power plants, chrome carbide coatings were prepared by PIRAC (Powder Immersion Reaction Assisted Coating) on T/P24 at 700-1000°C. Microstructure and phase composition of the obtained surface layers were characterized employing X-ray diffraction and scanning electron microscopy with chemical analysis (SEM/EDS). Results showed that homogenous smooth chrome carbide coatings can be formed on the substrate. Phase composition of the prepared coatings are differs with PIRAC temperatures. Prepared at lower temperatures or short times treatment, Cr23C6, Cr7C3 and Cr3C2 can be detected in the coatings. While, at higher temperatures or longer treatment times, Cr23C6 is subtotal phase of the produced coating. Moreover, the lower the PIRAC temperature is, the more of Cr7C3 and Cr3C2 are. Thermodynamics calculation based on Gibbs free energy is applied to explain phase composition difference of the coatings.


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