10 results on '"Tsatsulnikov, A. F."'
Search Results
2. Resonant optical reflection from a GaN/(Al,Ga)N excitonic Bragg structure.
- Author
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Ivanov, A. A., Chaldyshev, V. V., Zavarin, E. E., Sakharov, A. V., Lundin, W. V., and Tsatsulnikov, A. F.
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OPTICAL reflection ,QUANTUM wells ,ELECTROMAGNETIC coupling ,OPTICAL spectra ,EXCITON theory ,BRAGG gratings - Abstract
We experimentally demonstrate the formation of a superradiant optical mode in the room-temperature reflection spectra from a resonant Bragg structure composed of 30 equidistant GaN quantum wells separated by (Al,Ga)N barriers. The mode arises when the condition of the Bragg diffraction is fulfilled at the wavelength corresponding to the energy of the quasi-two-dimensional excitons in the quantum wells. It manifests itself as a significant increase in the amplitude and a change in the shape of the resonant optical reflection due to the electromagnetic coupling of the excitons. By modeling of the optical spectra, we evaluate the radiative and non-radiative broadening parameters of the excitonic states in the GaN quantum wells, which appear to be 0.4 ± 0.02 and 40 ± 5 meV, correspondingly, for the resonant exciton energy of 3.605 eV. The resonant Bragg structure based on the periodic sequence of the GaN quantum wells demonstrates an efficient coupling of photons and excitons at room temperature, which makes it promising for device applications. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Critical spatial disorder in InGaN resonant Bragg structures.
- Author
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Ivanov, A. A., Chaldyshev, V. V., Ushanov, V. I., Zavarin, E. E., Sakharov, A. V., Lundin, W. V., and Tsatsulnikov, A. F.
- Subjects
INDIUM gallium nitride ,OPTICAL reflection ,EXCITON theory ,QUANTUM wells ,OPTICAL spectra ,STANDARD deviations - Abstract
We study a disorder-induced transformation of the resonant optical reflection from a nearly periodic system of quasi-2D excitons in the InGaN quantum wells arranged as a resonant Bragg structure (RBS). We show that there is a critical deviation from the exact periodicity when the reflection by a single super-radiant exciton–polariton mode is transformed into a multimode spectrum. This critical disorder appears to be inversely proportional to the number of periods in the RBS. Using a numerical model which describes the experimentally observed optical spectra, we found the critical standard deviation from exact periodicity to be 1.76%, 1.0%, and 0.45% for InGaN-based RBS with 60, 100, and 200 periods, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
4. Room temperature exciton-polariton resonant reflection and suppressed absorption in periodic systems of InGaN quantum wells.
- Author
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Bolshakov, A. S., Chaldyshev, V. V., Zavarin, E. E., Sakharov, A. V., Lundin, W. V., Tsatsulnikov, A. F., and Yagovkina, M. A.
- Subjects
QUANTUM wells ,TWO-dimensional materials (Nanotechnology) ,EXCITON theory ,POLARITONS ,LIGHT absorption ,X-ray diffraction ,BRAGG'S law (Physics) ,BRAGG'S X-ray spectrometer - Abstract
We studied the optical properties of periodic InGaN/GaN multiple quantum well systems with different numbers of periods. A resonant increase in the optical reflection and simultaneous suppression of the optical absorption have been revealed experimentally at room temperature when the Bragg and exciton resonances were tuned to each other. Numerical modeling with a single set of parameters gave a quantitatively accurate fit of the experimental reflection and transmission spectra in a wide wavelength range and various angles of the light incidence. The model included both exciton resonance and non-resonant band-to-band transitions in the InGaN quantum wells, as well as Rayleigh light scattering in the GaN buffer layer. The analysis also involved x-ray diffraction and photoluminescence data. It allowed us to determine the key parameters of the structure. In particular, the radiative broadening of the InGaN QW excitons was evaluated as 0.20 ± 0.02 meV. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
5. Emission spectrum control in monolithic blue-cyan dichromatic light-emitting diodes.
- Author
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Arteev, D S, Karpov, S Y, Sakharov, A V, Nikolaev, A E, Usov, S O, Lundin, W V, and Tsatsulnikov, A F
- Subjects
MOLECULAR spectra ,EMISSION control ,LIGHT emitting diodes ,QUANTUM wells - Abstract
InGaN-based dichromatic light emitting diodes (LEDs) emitting in the blue and cyan spectral ranges simultaneously, are investigated both experimentally and theoretically. Two main approaches to controlling the ratio of blue-to-cyan components in the emission spectrum are suggested and analyzed: (i) thickness variation of the GaN barrier between the blue and cyan quantum wells and (ii) optimization of the barrier doping with n- or p-type impurities. Detailed examination of the approaches is carried out in order to understand their capabilities for intentional variation of the blue-to-cyan ratio in a wide range. Based on numerical simulations, a novel mechanism, invoking enhanced Shockley–Read–Hall recombination in the barrier and underlying both approaches, is suggested and discussed. It is shown that proposed design of the monolithic blue-cyan LEDs does not result in substantial decrease of the LED emission efficiency compared to monochromatic blue or cyan reference samples. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
6. Luminescence Line Broadening Caused by Alloy Disorder in InGaN Quantum Wells.
- Author
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Arteev, D. S., Sakharov, A. V., Lundin, W. V., Zavarin, E. E., Zakheim, D. A., and Tsatsulnikov, A. F.
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QUANTUM wells ,LUMINESCENCE ,ALLOYS ,MOLECULAR spectra ,INDIUM ,GALLIUM - Abstract
The broadening of the spectral linewidth of the GaN/InGaN/GaN quantum wells caused by the random distribution of indium and gallium atoms in the cation sublattice was analyzed theoretically. The calculated values of the full width at half maximum of the emission spectra at low temperature are much smaller than the usually observed experimental values, indicating that the emission linewidth of the InGaN quantum wells is mostly determined by other broadening mechanisms (e.g. indium clustering, quantum well width fluctuations, background impurity broadening, etc.). [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
7. Formation of three-dimensional islands in the active region of InGaN based light emitting diodes using a growth interruption approach
- Author
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Tsatsulnikov, Andrei F., Lundin, Wsevolod V., Sakharov, Alexei V., Nikolaev, Andrey E., Zavarin, E.E., Usov, S.O., Yagovkina, Maria A., Hÿtch, Martin, Korytov, Maxim, Cherkashin, Nikolay, Ioffe Physical-Technical Institute, Russian Academy of Sciences [Moscow] ( RAS ), Centre d'élaboration de matériaux et d'études structurales ( CEMES ), Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Centre National de la Recherche Scientifique ( CNRS ), Matériaux et dispositifs pour l'Electronique et le Magnétisme ( CEMES-MEM ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Centre National de la Recherche Scientifique ( CNRS ) -Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), A.F. Ioffe Physical-Technical Institute, Russian Academy of Sciences [Moscow] (RAS), Centre d'élaboration de matériaux et d'études structurales (CEMES), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Matériaux et dispositifs pour l'Electronique et le Magnétisme (CEMES-MEM), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3)
- Subjects
010302 applied physics ,Luminescence ,Light Emitting Diodes ,Metalorganic Vapor Phase Epitaxy ,[ PHYS.COND.CM-MS ] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Growth Interruption ,[SPI.TRON]Engineering Sciences [physics]/Electronics ,[ SPI.TRON ] Engineering Sciences [physics]/Electronics ,Quantum Wells ,0103 physical sciences ,Indium Gallium Nitride ,Quantum Dots ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,General Materials Science ,0210 nano-technology - Abstract
cited By 4; International audience; Here, we develop a technological approach to the formation of three-dimensional island-like structures in the active medium of InGaN/GaN based light emitting diodes with an enhanced efficiency with respect to reference quantum wells emitting at the same wavelengths. The reference structures contain two-dimensional In x Ga1– x N quantum wells with x ≤ 18% immediately overgrown after their formation. The method consists in the application of a growth interruption in N2 or N2–H2 mixed atmospheres at different H2 flows and times after the deposition of In0.18Ga0.82N quantum wells, prior to their overgrowth by a GaN layer. The growth interruptions allow a controlled blue shift of the emission peak position with respect to that of the In0.18Ga0.82N structure. The integrated photoluminescence intensity of the so-formed structures is about 1.5 times higher than that of the reference structures emitting at the same peak wavelengths. Light emitting diode structures subjected to growth interruption exhibit higher external quantum efficiency than the reference structures emitting at the same wavelengths. We demonstrate that the observed phenomenon is related to a better charge carrier confinement within a quantum well due to the transformation of planar InGaN layers into laterally connected flat islands.
- Published
- 2015
8. Optical lattices of InGaN quantum well excitons.
- Author
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Chaldyshev, V. V., Bolshakov, A. S., Zavarin, E. E., Sakharov, A. V., Lundin, W. V., Tsatsulnikov, A. F., Yagovkina, M. A., Kim, Taek, and Park, Youngsoo
- Subjects
OPTICAL lattices ,QUANTUM wells ,INDIUM alloys ,GALLIUM nitride ,ENERGY-band theory of solids - Abstract
We demonstrate optical Bragg lattices formed by quasi-two-dimensional excitons in periodic systems of the InGaN quantum wells separated by the GaN barriers. When the Bragg resonance and exciton-polariton resonance are tuned to each-other, the medium exhibits an exciton-mediated resonantly enhanced optical Bragg reflection. The enhancement factor appeared to be larger than 2 for the system of 60 quantum wells. Owing to a high binding energy and oscillator strength of the excitons in InGaN quantum wells, the resonant enhancement was achieved at room temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
9. The use of short-period InGaN/GaN superlattices in blue-region light-emitting diodes.
- Author
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Sizov, V. S., Tsatsulnikov, A. F., Sakharov, A. V., Lundin, W. V., Zavarin, E. E., Cherkashin, N. A., Hÿtch, M. J., Nikolaev, A. E., Mintairov, A. M., Yan He, and Merz, J. L.
- Subjects
- *
LIGHT emitting diodes , *SUPERLATTICES , *QUANTUM dots , *QUANTUM wells , *QUANTUM efficiency , *EPITAXY - Abstract
Optical and light-emitting diode structures with an active InGaN region containing short-period InGaN/GaN superlattices are studied. It is shown that short-period superlattices are thin two-dimensional layers with a relatively low In content that contain inclusions with a high In content 1–3 nm thick. Inclusions manifest themselves from the point of view of optical properties as a nonuniform array of quantum dots involved in a residual quantum well. The use of short-period superlattices in light-emitting diode structures allows one to decrease the concentration of nonradiative centers, as well as to increase the injection of carriers in the active region due to an increase in the effective height of the AlGaN barrier, which in general leads to an increase in the quantum efficiency of light-emitting diodes. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
10. Deep Green And Monolithic White LEDs Based On Combination Of Short-Period InGaN/GaN Superlattice And InGaN QWs.
- Author
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Tsatsulnikov, A. F., Lundin, W. V., Sakharov, A. V., Zavarin, E. E., Usov, S. O., Nikolaev, A. E., Kryzhanovskaya, N. V., Chernyakov, A. E., Zakgeim, A. L., Cherkashin, N. A., and Hytch, M.
- Subjects
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LIGHT emitting diodes , *GALLIUM nitride , *INDIUM compounds , *SUPERLATTICES , *QUANTUM wells , *OPTICAL properties of semiconductors , *ELECTRONIC structure - Abstract
This work presents the results of the investigation of approaches to the synthesis of the active region of LED with extended optical range. Combination of short-period InGaN/GaN superlattice and InGaN quantum well was applied to extend optical range of emission up to 560 nm. Monolithic white LED structures containing two blue and one green QWs separated by the short-period InGaN/GaN superlattice were grown with external quantum efficiency up to 5-6%. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
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