Search Results - "Helava, H."

Carbon defects as sources of the green and yellow luminescence bands in undoped GaN by Reshchikov, M. A., Demchenko, D. O., Usikov, A., Helava, H., Makarov, Yu

“…In high-purity GaN grown by hydride vapor phase epitaxy, the commonly observed yellow luminescence (YL) band gives way to a green luminescence (GL) band at…”
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Two yellow luminescence bands in undoped GaN by Reshchikov, M. A., McNamara, J. D., Helava, H., Usikov, A., Makarov, Yu

“…Two yellow luminescence bands related to different defects have been revealed in undoped GaN grown by hydride vapor phase epitaxy (HVPE). One of them, labeled…”
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Evaluation of the concentration of point defects in GaN by Reshchikov, M. A., Usikov, A., Helava, H., Makarov, Yu, Prozheeva, V., Makkonen, I., Tuomisto, F., Leach, J. H., Udwary, K.

“…Photoluminescence (PL) was used to estimate the concentration of point defects in GaN. The results are compared with data from positron annihilation…”
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Fine structure of the red luminescence band in undoped GaN by Reshchikov, M. A., Usikov, A., Helava, H., Makarov, Yu

“…Many point defects in GaN responsible for broad photoluminescence (PL) bands remain unidentified. Their presence in thick GaN layers grown by hydride vapor…”
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Determination of the concentration of impurities in GaN from photoluminescence and secondary-ion mass spectrometry by Reshchikov, M. A., Vorobiov, M., Andrieiev, O., Ding, K., Izyumskaya, N., Avrutin, V., Usikov, A., Helava, H., Makarov, Yu

“…Photoluminescence (PL) was used to estimate the concentration of carbon in GaN grown by hydride vapor phase epitaxy (HVPE). The PL data were compared with…”
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Determination of the electron-capture coefficients and the concentration of free electrons in GaN from time-resolved photoluminescence by Reshchikov, M. A., McNamara, J. D., Toporkov, M., Avrutin, V., Morkoç, H., Usikov, A., Helava, H., Makarov, Yu

“…Point defects in high-purity GaN layers grown by hydride vapor phase epitaxy are studied by steady-state and time-resolved photoluminescence (PL). The…”
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Defect-Related Luminescence in Undoped GaN Grown by HVPE by Reshchikov, M.A., Usikov, A., Helava, H., Makarov, Yu

“…Hydride vapor phase epitaxy (HVPE) is used for the growth of low-defect GaN. We have grown undoped films on sapphire and investigated them using steady-state…”
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Experimental and theoretical analysis of sublimation growth of AlN bulk crystals by Makarov, Yu.N., Avdeev, O.V., Barash, I.S., Bazarevskiy, D.S., Chemekova, T.Yu, Mokhov, E.N., Nagalyuk, S.S., Roenkov, A.D., Segal, A.S., Vodakov, Yu.A., Ramm, M.G., Davis, S., Huminic, G., Helava, H.

“…The current status of sublimation growth of aluminum nitride (AlN) bulk crystals is discussed. Growth of AlN single-crystal layers on silicon carbide (SiC)…”
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Effect of Capping on Electrical and Optical Properties of GaN Layers Grown by HVPE by Reshchikov, M. A., Usikov, A., Helava, H., Makarov, Yu, Puzyk, M. V., Papchenko, B. P.

“…Gallium nitride, grown by hydride vapor phase epitaxy and capped with a thin AlGaN layer, was studied by photoluminescence (PL) methods. The concentration of…”
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Sublimation growth of AlN bulk crystals in Ta crucibles by Mokhov, E.N., Avdeev, O.V., Barash, I.S., Chemekova, T.Yu, Roenkov, A.D., Segal, A.S., Wolfson, A.A., Makarov, Yu.N., Ramm, M.G., Helava, H.

“…AlN single crystals of 0.5 in diameter and up to 10–12 mm long have been grown by sublimation/recondensation in pre-treated tantalum crucibles. Growth of 45 mm…”
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Study of the characteristics of ultraviolet light-emitting diodes based on GaN/AlGaN heterostructures grown by chloride-hydride vapor-phase epitaxy by Solomonov, A. V., Tarasov, S. A., Men’kovich, E. A., Lamkin, I. A., Kurin, S. Yu, Antipov, A. A., Barash, I. S., Roenkov, A. D., Helava, H., Makarov, Yu. N.

“…The results of work on developing and studying ultraviolet (UV) light-emitting diodes (LEDs) based on GaN/AlGaN heterostructures fabricated on Al 2 O 3 (0001)…”
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On the fractal nature of light-emitting structures based on III–N nanomaterials and related phenomena by Petrov, V. N., Sidorov, V. G., Talnishnikh, N. A., Chernyakov, A. E., Shabunina, E. I., Shmidt, N. M., Usikov, A. S., Helava, H., Makarov, Yu. N.

“…It is shown that a three-dimensional fractal–percolation system is formed in nanomaterials of light-emitting InGaN/GaN and AlGaN/GaN structures in the presence…”
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Characterization of bulk AlN crystals with positron annihilation spectroscopy by Tuomisto, F., Mäki, J.-M., Chemekova, T.Yu, Makarov, Yu.N., Avdeev, O.V., Mokhov, E.N., Segal, A.S., Ramm, M.G., Davis, S., Huminic, G., Helava, H., Bickermann, M., Epelbaum, B.M.

“…We have applied positron annihilation spectroscopy to study in-grown vacancy defects in bulk aluminium nitride (AlN) crystals grown by physical vapor…”
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Structural, electrical and luminescent characteristics of ultraviolet light emitting structures grown by hydride vapor phase epitaxy by A.Y. Polyakov, Jin-Hyeon Yun, A.S. Usikov, E.B. Yakimov, N.B. Smirnov, K.D. Shcherbachev, H. Helava, Y.N. Makarov, S.Y. Kurin, N.M. Shmidt, O.I. Rabinovich, S.I. Didenko, S.A. Tarelkin, B.P. Papchenko, In-Hwan Lee

“…Electrical and luminescent properties of near-UV light emitting diode structures (LEDs) prepared by hydride vapor phase epitaxy (HVPE) were studied. Variations…”
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Short-period superlattices of AlN∕Al0.08Ga0.92N grown on AlN substrates by Nikishin, S. A., Borisov, B. A., Chandolu, A., Kuryatkov, V. V., Temkin, H., Holtz, M., Mokhov, E. N., Makarov, Yu, Helava, H.

“…High-quality short-period superlattices of AlN∕Al0.08Ga0.92N have been grown by gas-source molecular-beam epitaxy with ammonia on Al face of AlN (0001)…”
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Photoelectric converters in a system with spectral splitting of the solar energy by Kurin, S. Yu, Doronin, V. D., Antipov, A. A., Papchenko, B. P., Helava, H., Voronova, M. I., Usikov, A. S., Makarov, Yu. N., Eidel’man, K. B.

“…The results of modeling photoelectric converters in a system with spectral splitting of solar energy are detailed. The solar radiation in this system is…”
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Deep centers in bulk AlN and their relation to low-angle dislocation boundaries by Polyakov, A.Y., Smirnov, N.B., Govorkov, A.V., Yugova, T.G., Scherbatchev, K.D., Avdeev, O.A., Chemekova, T.Yu, Mokhov, E.N., Nagalyuk, S.S., Helava, H., Makarov, Yu.N.

“…Structural properties, electrical properties, deep traps spectra, optical properties of bulk 50-mm-diameter AlN crystals prepared by physical vapor transport…”
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Homoepitaxy of GaN on polished bulk single crystals by metalorganic chemical vapor deposition by Ponce, F. A., Bour, D. P., Götz, W., Johnson, N. M., Helava, H. I., Grzegory, I., Jun, J., Porowski, S.

“…Bulk single crystals of GaN were used for epitaxial growth of GaN by metalorganic chemical vapor deposition. Photoluminescence (at 2 K) from polished…”
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Study of mechanisms responsible for the efficiency degradation of the III-nitrides light emitting diodes by Shmidt, N.M., Usikov, A.S., Shabunina, E.I., Chernyakov, A.E., Kurin, S.Yu, Makarov, Yu.N., Helava, H., Papchenko, B.P.

“…The results for external quantum efficiency degradation of two types of light emitting diodes based on III-nitrides: blue and ultraviolet ones are presented…”
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Modeling of facet formation in SiC bulk crystal growth by Matukov, I.D., Kalinin, D.S., Bogdanov, M.V., Karpov, S.Yu, Ofengeim, D.Kh, Ramm, M.S., Barash, J.S., Mokhov, E.N., Roenkov, A.D., Vodakov, Yu.A., Ramm, M.G., Helava, H., Makarov, Yu.N.

“…Control of the crystallization front profile is of great importance for various aspects of bulk SiC crystal growth by physical vapor transport. The structural…”
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