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Tytuł:
Optical Properties of InAs Quantum Dots
Autorzy:
Willander, M.
Zhao, Q. X.
Jacob, A. P.
Wang, S. M.
Wei, Y. Q.
Powiązania:
https://bibliotekanauki.pl/articles/2035579.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
78.55.Cr
Opis:
InAs quantum dots grown on GaAs substrate were investigated by optical spectroscopy. We particularly emphasized on the photoluminescence intensity, the stability of the photoluminescence intensity versus temperatures and wavelength of the InAs dot emission at various thermal treatments and different structures. We found that hydrogen can strongly passivate nonradiative centers without causing any structure degradation, and both n- and p-type modulation doping can reduce the decrease in the photoluminescence intensity when the sample temperature increases from the helium temperature to room temperature. The emission wavelength and the efficiency of the InAs quantum dots can also be manipulated by choosing proper materials of cap layer.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 567-576
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Single GaN/AlGaN Quantum Dot Spectroscopy
Autorzy:
Surowiecka, K.
Wysmołek, A.
Stępniewski, R.
Bożek, R.
Pakuła, K.
Baranowski, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2047382.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Microphotoluminescence of low-density GaN/Al$\text{}_{x}$Ga$\text{}_{1-x}$N quantum dots grown by metal-organic vapor phase epitaxy using in situ etching of AlGaN is presented. The detailed analysis of the emission from these structures enables the observation of pairs of lines separated by the energy up to 3 meV. They behave in a different way under different excitation power that suggests that this doublet structure can be associated with the exciton and trion (or biexciton recombination). It is observed that for different quantum dots the energy of the charged exciton complex emission could be higher or lower than the neutral exciton one. It is discussed in terms of a competition between attractive e-h and repulsive e-e (h-h) Coulomb interaction that occurs because of the existence of the built-in electric field that separates electrons and holes in the dot.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 233-236
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temporal Evolution of Multi-Carrier Complexes in Single GaN/AlGaN Quantum Dots
Autorzy:
Surowiecka, K.
Wysmołek, A.
Stępniewski, R.
Bożek, R.
Pakuła, K.
Baranowski, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/2044542.pdf
Data publikacji:
2005-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Microphotoluminescence of low-density GaN/Al$\text{}_{x}$Ga$\text{}_{1-x}$N quantum dots grown by metal-organic vapor phase epitaxy using in situ etching of AlGaN is presented. The narrow lines in the microphotoluminescence spectra due to the single quantum dots are observed. Both energy and intensity of these lines show temporal fluctuations. Statistical analysis based on the correlation matrix allowed us to identify objects, which are affected by photo-induced electric field fluctuations. Relations between emission lines participating in the spectrum are discussed.
Źródło:
Acta Physica Polonica A; 2005, 108, 5; 879-884
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Spins in Self-Assembled (In,Ga)As/GaAs Quantum Dots Studied by Pump-Probe Faraday Rotation
Autorzy:
Greilich, A.
Yugova, I. A.
Oulton, R.
Zhukov, E. A.
Yakovlev, D. R.
Bayer, M.
Shabaev, A.
Efros, Al. L.
Stavarache, V.
Reuter, D.
Wieck, A. D.
Powiązania:
https://bibliotekanauki.pl/articles/2046975.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Static and dynamic properties of electron spins in self-assembled (In,Ga)As/GaAs quantum dots which contain on average a single electron per dot were studied by pump-probe Faraday rotation. Examples given here are the g-factor tensor components as well as the dephasing time T*$\text{}_{2}$ within a dot ensemble.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 287-293
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time Evolution of the Microluminescence Energy οf GaN/AlGaN Quantum Dots
Autorzy:
Surowiecka, K.
Wysmołek, A.
Stępniewski, R.
Bożek, R.
Pakuła, K.
Baranowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791354.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Time evolution of the microphotoluminescence from low-density GaN/$Al_{x}Ga_{1-x}N$ quantum dots grown by metal organic chemical vapor deposition using in situ etching of AlGaN is presented. The observed effect is related to the energy changes that begin immediately after sample illumination with the exciting laser light and saturate after some time. Typically, the luminescence energy decreases and the change is exponential with characteristic times in a range between several dozen and several hundred seconds. However, sometimes we observed the energy increase with characteristic times in a range between several and a few hundred seconds. The obtained results are discussed in terms of the metastable change of the electric field, induced by spontaneous polarization present in GaN/AlGaN structure (in the growth direction), and strain- or defect-induced changes of the electric field in the vicinity of the dot.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 933-935
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fine Structure of Neutral Excitons in Single GaAlAs Quantum Dots
Autorzy:
Molas, M.
Gołasa, K.
Piętka, B.
Potemski, M.
Babiński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1403612.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Optical anisotropy of neutral excitons in GaAlAs/AlAs quantum dots is investigated. Low-temperature polarization-sensitive photoluminescence measurements of single quantum dots are performed. It is found that neutral excitons (X) in the quantum dots exhibit a fine structure splitting. The fine structure splitting ranges from 10 μeV to 100 μeV and correlates with the X energy. The polarization axis of the fine structure splitting is well oriented along [110] crystallographic direction of a substrate. The orientation is attributed to the elongation of GaAlAs/AlAs quantum dots in the [110] direction of the substrate.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 988-990
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Fine Structure of a Triexciton in Single InAs/GaAs Quantum Dots
Autorzy:
Molas, M.
Gołasa, K.
Furman, M.
Lapointe, J.
Wasilewski, Z.
Potemski, M.
Babiński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1403615.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Results of experimental study of multiexcitonic emission related to the p-shell of single self-assembled InAs/GaAs quantum dots are presented. Optical properties of a first emission line to appear from the p-shell of a strongly excited quantum dots are investigated using low-temperature polarization-sensitive micro-photoluminescence measurements. The emission line is attributed to the recombination of a complex of three electrons and holes confined in a dot (neutral triexciton), 3X. It is found that the emission consists of two linearly polarized components and the fine structure splitting is larger than the respective splitting of a neutral exciton. The optical anisotropy of the 3X emission is related to the anisotropy of the quantum dot localizing potential. The axis of the 3X optical anisotropy changes from dot to dot covering broad range within ± 50 degrees with respect to the axis defined by the optical anisotropy of a neutral exciton (X). Possible origin of the deviation is discussed.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 991-993
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of Excitons in Quantum Dots with a Weak Confinement
Autorzy:
Gołasa, K.
Molas, M.
Goryca, M.
Kazimierczuk, T.
Smoleński, T.
Koperski, M.
Golnik, A.
Kossacki, P.
Potemski, M.
Wasilewski, Z.
Babiński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399080.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
Statistical properties of neutral excitons, biexcitons and trions confined to natural quantum dots formed in the InAs/GaAs wetting layer are reported. The correlation of the trion binding energy and the biexciton binding energy was found. Magnetospectroscopic measurements of the excitons revealed also the correlation of excitonic effective $g^\ast $ factor of an exciton with the biexciton binding energy. The qualitative picture of the effect of quantum confinement on the observed correlations is presented.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 781-784
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Real-Space Mapping of Exciton Wave Functions in a Quantum Dot with Near-Field Optical Imaging Spectroscopy
Autorzy:
Saiki, T.
Matsuda, K.
Nomura, S.
Mihara, M.
Aoyagi, Y.
Nair, S.
Takagahara, T.
Powiązania:
https://bibliotekanauki.pl/articles/2036895.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
An exciton confined within a quantum dot acts as a two-level quantum system, and is one of the most promising candidates for quantum computing and quantum information processing. The real-space optical probing of the quantum eigenstates in a single quantum dot and coupled quantum dots should be developed toward the realization of quantum photonic devices, where their wave functions are dynamically controlled by coherent optical techniques. Here we apply near-field photoluminescence imaging spectroscopy with a high spatial resolution of 30 nm to map out the centre-of-mass wave function of an exciton confined in a GaAs quantum dot. The spatial profile of the exciton emission, which reflects the shape of a monolayer-high island, differs from that of biexciton emission, due to different distributions of the polarization field for the exciton and biexciton recombinations.
Źródło:
Acta Physica Polonica A; 2003, 104, 3-4; 281-287
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Confinement in InAs/GaAs Systems with Self-Assembled Quantum Dots Grown Using In-Flush Technique
Autorzy:
Molas, M.
Kuldová, K.
Borysiuk, J.
Wasilewski, Z.
Babiński, A.
Powiązania:
https://bibliotekanauki.pl/articles/2048050.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.67.Hc
Opis:
The effect of In-flush technique application to the MBE-grown structure with self-assembled quantum dots is investigated in this work. The microphotoluminescence from structures with the InAs/GaAs dots grown with and without the In-flush has been investigated. We focus our attention on "not fully developed" dots, which can be clearly distinguished in the spectrum. The dots have also been identified in the transmission electron microscopy analysis of the structures. The In-flush does not influence a broad energy range of those features. Instead we have found that the anisotropic exchange energy splitting of neutral excitons confined in those in the structure grown with In-flush is substantially lower that the splitting in the structure with no In-flush. This observation confirms that the In-flush leads not only to better uniformity of self-assembled quantum dots but also to reduction of lateral potential, anisotropy, which is believed to result in the neutral exciton splitting.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 624-626
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control of Exciton Fine Structure Splitting in Quantum Dots
Autorzy:
Stevenson, R. M.
Young, R. J.
Atkinson, P.
Cooper, K.
Ritchie, D. A.
Shields, A. J.
Powiązania:
https://bibliotekanauki.pl/articles/2046985.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.67.Mn
78.67.Hc
78.55.Cr
Opis:
Quantum dots have been identified as potential sources of entangled photon pairs, essential for many applications in quantum information. However, in practice structural properties of the dots result in polarisation splitting of the emission lines, which has prevented the realisation of such a source. Here, we present two techniques developed to control the polarisation splitting in a quantum dot both irreversibly and reversibly. We find that the splitting is strongly dependent upon the emission energy, or lateral confinement, of the quantum dot. Thus by precise control of the InAs deposition thickness, it is possible to produce ensembles from which dots with zero polarisation splitting can be easily selected. Additionally, we demonstrate that by using modest in-plane magnetic fields to partially mix the bright and dark exciton states, the polarisation splitting can be reversibly tuned to zero for most dots of a certain type. Finally, we demonstrate the emission of triggered entangled photon pairs from a quantum dot with approximately zero splitting with fidelity >70%.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 311-318
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Role of Internal Electric Fields in III-N Quantum Structure
Autorzy:
Perlin, P.
Łepkowski, S. P.
Teisseyre, H.
Suski, T.
Grandjean, N.
Massies, J.
Powiązania:
https://bibliotekanauki.pl/articles/2027477.pdf
Data publikacji:
2001-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Hp
78.55.Cr
78.67.Hc
Opis:
Binary nitrides: of wurtzite GaN, AlN, InN, and their solid solutions represent a family of semiconductors of crucial importance for modern optoelectronics. Strained quantum wells, like GaN/AlGaN and specially InGaN/GaN, form active layers of the light emitters working in green-UV part of the spectrum. The operation of these devices strongly depends on the emission spectra of considered quantum structures which are greatly influenced by the presence of built-in electric fields. The electric field acting via quantum confined Stark effect in the mentioned structures changes the energies and intensity of the emitted light. The effect can lead to the spectral shift of a photo- and electroluminescence by many hundreds of meV. In this review we will briefly cover the influence of internal electric fields on both optical and electrical properties of nitride based heterostructures and quantum wells. We would like to draw reader's attention to the usefulness of high-pressure investigation in the study of electric fields in nitrides and to show how the interpretation of these experiments influences the way we calculate the electric fields in the quantum structures.
Źródło:
Acta Physica Polonica A; 2001, 100, 2; 261-270
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neutral and Charged Excitons Localized in the InAs/GaAs Wetting Layer
Autorzy:
Babiński, A.
Czyż, M.
Golnik, A.
Borysiuk, J.
Kret, S.
Raymond, S.
Lapointe, J.
Wasilewski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1811914.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
78.55.Cr
78.67.Hc
Opis:
It has recently been shown that potential fluctuations in a wetting layer, which accompanies InAs/GaAs quantum dots can localize excitons. Neutral excitons and biexcitons and charged excitons were identified. In this communication we report on studies of properties of the excitons over wide temperature range (T < 70 K). The micro-photoluminescence measurements enable investigation of excitons localized in a single potential fluctuation. Temperature-induced broadening of the neutral exciton as well as a quenching of the charged exciton at temperatures higher than 50 K are observed and discussed.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1055-1060
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Properties of Multi-Stacked InAs Quantum Dots Embedded in GaAs/InGaAs Strained Layer and its Annealing Behaviors
Autorzy:
Kim, D.
Kim, G.
Jeon, S.
Cho, M.
Choi, H.
Kim, M.
Lee, D.
Kim, J.
Eom, G.
Leem, J.
Powiązania:
https://bibliotekanauki.pl/articles/1537752.pdf
Data publikacji:
2010-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
78.55.Cr
81.05.Ea
Opis:
Multi-stacked InAs QDs embedded in ten periods of GaAs/$In_{0.1}Ga_{0.9}As$ strained layers were grown by MBE and their optical properties were investigated by using PL spectroscopy. For the QDs embedded in ten periods of GaAs/$In_{0.1}Ga_{0.9}As$ strained layers, the PL intensity is enhanced about 4.7 times and a narrower FWHM of 26 meV is observed compared to those of the conventional multi-stacked QDs. The PL spectra of the InAs QDs show blue-shifts of about 50 meV with increasing annealing temperature up to 850°C. At annealing temperature of 600°C, the FWHM of the PL peak is reduced to 16 meV and PL intensity is enhanced compared to those of the as-grown sample, which indicates improvement of size uniformity and crystal quality of the QDs.
Źródło:
Acta Physica Polonica A; 2010, 117, 6; 941-944
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoreflectance of Epitaxial InGaAs Quantum Rods
Autorzy:
Nedzinskas, R.
Karpus, V.
Čechavičius, B.
Kavaliauskas, J.
Valušis, G.
Li, L.
Khanna, S.
Linfield, E.
Powiązania:
https://bibliotekanauki.pl/articles/1505523.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
78.55.Cr
81.05.Ea
Opis:
Photoreflectance spectroscopy and photoluminescence have been used to study the optical properties and electronic structure of InGaAs quantum rods grown by molecular beam epitaxy. Spectral features associated with interband optical transitions localized in the quantum rod and the surrounding quantum well regions are examined. Experimental results are compared with calculations performed within the envelope function approximation. A red shift of the quantum rod- and a blue shift of the quantum well-related optical transitions, along with a significant increase in PL intensity have been observed if an $As_4$ source is used instead of an $As_2$ source during the molecular beam epitaxial growth.
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 164-166
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 28

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