| 1. |
- Khranovskyy, Volodymyr, et al.
(author)
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Luminescence anisotropy of ZnO microrods
- 2012
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In: Journal of Luminescence. - : Elsevier. - 0022-2313 .- 1872-7883. ; 132:10, s. 2643-2647
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Journal article (peer-reviewed)abstract
- The local features of light emission from ZnO microrods were studied: it is revealed that ZnO luminescence spectra are significantly influenced by the crystal morphology. It is shown that the near and edge ultraviolet emission occurs primarily from the top (0001) planes of ZnO microrods; while the defect related visible emission was found to occur dominantly from the side facets. The room temperature cathodoluminescence analysis revealed that visible emission consists of a few overlapping peaks, arising due to recombination on common points and surface defects (Zn-i, V-o, V-o(O)/V-o(**) V-o(**) and surface defects.). While at low temperature, only the luminescence due to neutral donor bound exciton ((DX)-X-0) emission is observed. The data obtained suggest that the light emission spectra of ZnO material of diverse morphology cannot be directly compared, although some common spectral features are present.
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| 2. |
- Shtepliuk, I, et al.
(author)
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Electrical properties of n-Zn0.94Cd0.06O/p-SiC heterostructures
- 2013
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In: Solid-State Electronics. - : Elsevier BV. - 0038-1101 .- 1879-2405. ; 81, s. 72-77
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Journal article (peer-reviewed)abstract
- We report the low-temperature (250 °C) fabrication of n-ZnCdO/p-SiC heterostructures by direct current magnetron sputtering (DC MS) technique. As-grown heterostructures exhibit diode characteristics: current–voltage measurements showed a typical rectifying characteristic of a p–n junction and the presence of series resistance. It is found that the turn-on voltage of heterostructures depends on the acceptor concentration in p-SiC. Via Cd doping of ZnO the energy barrier for holes can be lowered, which promotes the hole injection from the p-type layer to the n-type layer as well as favors the radiative recombination in the n-ZnCdO layer.
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| 3. |
- Shtepliuk, I., et al.
(author)
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Phase Field Modeling of the Zn1-xCdxO Solid Solutions
- 2014
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In: Acta Physica Polonica. A. - : POLISH ACAD SCIENCES INST PHYSICS. - 0587-4246 .- 1898-794X. ; 126:5, s. 1079-1082
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Journal article (peer-reviewed)abstract
- The analysis of spinodal decomposition in the Zn1-xCdxO ternary alloy was carried out by means of the nonlinear Cahn-Hilliard equation. Interaction parameter as a function of composition x was provided by valence force field simulations and was used in this analysis. The morphological patterns for the ternary alloys with different Cd content (x = 5, 10, 50%) were experimentally obtained using the semi-implicit Fourier-spectral method. The simulated microstructure evolution Zn0.95Cd0.05O demonstrates that the microstructure having a form of bicontinuous worm-like network is evolved with the progress of aging. An effect of the phase-field mobility and the gradient energy on the microstructure evolution of the Zn1-xCdxO alloys is discussed. It was found that the higher driving force for the decomposition in the higher Cd content film results in a higher decomposition rate revealed by the simulations. The temporal evolution of the simulated Zn0.95Cd0.05O microstructure is in good agreement with experimental results, which have been obtained for this solid solution.
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| 4. |
- Shtepliuka, I., et al.
(author)
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Microstructure and luminescence dynamics of ZnCdO films with high Cd content deposited on different substrates by DC magnetron sputtering method
- 2013
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In: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 276, s. 550-557
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Journal article (peer-reviewed)abstract
- Investigation of Cd behavior in the ZnCdO alloys, where Cd content exceeds the solubility limit, is of importance due to possible impurity segregation and second phases' formation in this material. We have studied the Cd behavior in the Zn1-xCdxO films deposited by dc magnetron sputtering on different substrates: c-plane Al2O3, bare Si (1 0 0) and Au (45 nm)/Si (1 0 0). It is revealed that Cd content of 10 at. % in the target results in average 6-8 at. % of Cd in the films, depending on the substrate type. Structural analysis based on X-ray diffraction revealed the absence of Cd-related secondary phases. Time-resolved photoluminescence (TRPL) and high-resolution energy dispersive X-ray analysis (EDX) help to understand the recombination dynamics of spontaneous emission and to establish correlations between cadmium content and radiative lifetime. We have revealed that the internal quantum efficiency is influenced by the Cd content and defect concentration. It is suggested that increasing of the cadmium content results in the reduction of nonradiative recombination centers originating from point defects.
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