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Your search keyword '"Mikhailovskii V"' showing total 2 results
Start Over Author "Mikhailovskii V" Topic gallium nitride
2 results on '"Mikhailovskii V"'

1. Fine core structure and spectral luminescence features of freshly introduced dislocations in Fe-doped GaN.

Author

Shapenkov, S., Vyvenko, O., Ubyivovk, E., and Mikhailovskii, V.

Subjects
LUMINESCENCE, CATHODOLUMINESCENCE, SCANNING transmission electron microscopy, GALLIUM nitride, ELECTRON microscope techniques, DISLOCATION structure, SCREW dislocations
Abstract

Dislocations introduced by Vickers tip microindentation of an a-plane free-standing semi-insulating Fe-doped GaN halide vapor phase epitaxy (HVPE) crystal were investigated by means of cathodoluminescence and scanning transmission electron microscopy techniques. Detailed combined analyses of both spectral properties and the core structure of the introduced a-screw dislocations revealed that Fe-doped GaN exhibit not only dislocation-bound emission at ∼3.35 eV of perfect a-screw dislocations previously found in such kind of samples but also luminescent bands at 3.1–3.2 and 3.3 eV due to dissociated a-screw dislocations and extended dislocation nodes previously observed only in low-resistance n-GaN. For the first time, all these luminescent bands were observed together in the same sample. Structural studies revealed the coexistence of the dislocations with the dissociated and the perfect core as well as with extended dislocation nodes, thus establishing a correlation between previously observed luminescence bands and a fine dislocation core structure. [ABSTRACT FROM AUTHOR]

Published
2022
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2. Recombination-Related Properties of a-Screw Dislocations in GaN: A Combined CL, EBIC, TEM Study.

Author

Medvedev, O. S., Vyvenko, O. F., Bondarenko, A. S., Mikhailovskii, V. Yu., Ubyivovk, E. V., Peretzki, P., and Seibt, M.

Subjects
CATHODOLUMINESCENCE, SCREW dislocations, TRANSMISSION electron microscopy, CRYSTAL structure, BAND gaps, RECOMBINATION (Chemistry), GALLIUM nitride, ELECTRON beams
Abstract

Cathodoluminescence (CL), electron beam current (EBIC) and transmission electron microscopy (TEM) techniques have been applied to investigate recombination properties and structure of freshly introduced dislocations in low-ohmic GaN crystals. It was confirmed that the only a-screw dislocations exhibited an intense characteristic dislocation-related luminescence (DRL) which persisted up to room temperature and was red-shifted by about 0.3 eV with respect to the band gap energy not only in HVPE but also in MOCVD grown samples. EBIC contrast of the dislocations was found to be temperature independent indicating that the dislocation-related recombination level is situated below 200 meV with respect of conduction band minimum. With the increasing of the magnification of the dislocation TEM cross-sectional images they were found to disappear, probably, due to the recombination enhanced dislocation glide (REDG) under electron beam exposure which was immediately observed in CL investigations on a large scale. The stacking fault ribbon in the core of dissociated a-screw dislocation which form a quantum well for electrons was proposed to play an important role both in DRL spectrum formation and in REDG. [ABSTRACT FROM AUTHOR]

Published
2016
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