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- Aleksandrov, I.A., et al.
(författare)
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Linearly polarized photoluminescence from an ensemble of wurtzite GaN/AlN quantum dots
- 2010
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Ingår i: JETP Letters. - : Springer Science Business Media. - 0021-3640 .- 1090-6487. ; 91:9, s. 452-454
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Tidskriftsartikel (refereegranskat)abstract
- Microphotoluminescence from GaN/AlN quantum dots grown by molecular beam epitaxy on sapphire substrates along the (0001) axis has been studied. To produce quantum dots of different average sizes and densities, the nominal amount of deposited GaN has been varied from 1 to 4 ML. The density of the quantum dots was about 10(11) cm(-2), which corresponded to about 10(3) quantum dots excited in the experiments. The photo-luminescence from the quantum dots was linearly polarized and the maximum polarization degree (15%) has been observed for the sample with the lowest amount of deposited GaN. The photoluminescence intensity from this sample under continuous laser excitation decreased by more than two orders of magnitude for about 30 min and then stabilized. The photoluminescence intensity from other samples under continuous excitation remained constant. We suggest that a rather high polarization degree is caused by anisotropy in the strain and shape of the quantum dots formed near the dislocations, which also act as the centers of nonradiative recombination.
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| 2. |
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| 3. |
- Shamirzaev, T S, et al.
(författare)
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Atomic and energy structure of InAs/AlAs quantum dots
- 2008
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 78:8
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Tidskriftsartikel (refereegranskat)abstract
- The atomic structure and energy spectrum of InAs quantum dots (QDs) in an AlAs matrix have been experimentally studied by transmission electron microscopy (TEM) and steady-state photoluminescence (PL) combined with computational work. The degree of intermixing of InAs and AlAs has been investigated by means of TEM and PL compared with theoretical predictions and found to increase with increasing growth temperature and growth interruption. The band alignment in the QDs is shown to be of type I with the lowest conduction-band states at the direct Γ or at the indirect XXY minima of the QD conduction band, depending on the QD's size and composition. © 2008 The American Physical Society.
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| 4. |
- Zhuravlev, K S, et al.
(författare)
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Linear polarized photoluminescence from GaN quantum dots imbedded in AlN matrix
- 2010
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Ingår i: physica status solidi c. - : Wiley. - 1862-6351 .- 1610-1642.
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Konferensbidrag (refereegranskat)abstract
- We report microphotoluminescence studies of GaN/AlN quantum dots grown along the (0001) crystal axis by molecular-beam epitaxy on sapphire substrates. To obtain quantum dots with different density and size a nominal GaN coverage was varied from 1 to 4 monolayers. The highest density of quantum dots was about 1011 cm-2, so about 103 quantum dots was excited in experiments. We found that the photoluminescence intensity of a sample with the smallest amount of deposited GaN decreases in more than two orders of magnitude under continuous-wave laser exposure during about 30 minutes and then it remains stable. The photoluminescence intensity of the rest samples was time-independent quantity. The emission band of the former sample exhibits a prominent linear polarization along the growth plane. We assume that the quite high degree of polarization can be due anisotropy of strain and/or shape of the quantum dots formed near dislocations which act also as recombination centers causing photoluminescence quenching.
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| 5. |
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| 6. |
- Zhuravlev, K.S., et al.
(författare)
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Microphotoluminescence of GaN/AlN quantum dots grown by MBE
- 2006
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Ingår i: Physica Status Solidi. C, Current topics in solid state physics. - 1610-1634 .- 1610-1642. ; 3, s. 2048-2051
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Tidskriftsartikel (refereegranskat)abstract
- Presented at: The 6th International Conference on Nitride Semiconductors (ICNS6), Bremen, Germany, Aug 28-Sept 2, 2005
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