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- Karlsson, Fredrik, 1974-, et al.
(author)
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Carrier diffusion in the barrier enabling formation of charged excitons in InAs/GaAs quantum dots
- 2001
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In: XXX International School on the Physics of Semiconducting Compounds,2001. - : Polish Academy of Sciences, Institute of Physics. ; , s. 387-395
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Conference paper (peer-reviewed)abstract
- It is demonstrated that the photoluminescence spectra of single self-assembled quantum dots are very sensitive to the experimental conditions, such as excitation energy and crystal temperature. A qualitative explanation is given in terms of the effective diffusion of the photogenerated carriers, determined by the experimental conditions, which influence the capture probability and hence also the charge state of the quantum dots. This is proposed as a new tool to populate quantum dots with extra electrons in order to study phenomena involving charged excitons.
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| 2. |
- Karlsson, Fredrik, 1974-, et al.
(author)
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Temperature influence on optical charging of self-assembled InAs/GaAs semiconductor quantum dots
- 2001
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 78:19, s. 2952-2954
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Journal article (peer-reviewed)abstract
- It is demonstrated that the photoluminescence spectra of single self-assembled InAs/GaAs quantum dots are very sensitive to excitation energy and crystal temperature. This is qualitatively explained in terms of the effective diffusivity of photogenerated particles, which affects the capture probability of the quantum dot. As a consequence, this opens the possibility of controlling the average number of excess electrons in the quantum dot by optical means. This technique may be used as a simple tool to create and study charged exciton complexes without any specially fabricated samples. ⌐ 2001 American Institute of Physics.
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| 4. |
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| 5. |
- Paskov, Plamen, 1959-, et al.
(author)
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Internal structure of free excitons in GaN
- 2001
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In: Physica status solidi. B, Basic research. - 0370-1972 .- 1521-3951. ; 228:2, s. 467-470
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Journal article (peer-reviewed)abstract
- Polarized photoluminescence is used to study the fine structure of free excitons in thick GaN layers grown on differently oriented sapphire substrates. The singlet-triplet splitting of the A exciton is measured and the exchange interaction constant in GaN is determined. For the samples grown on the a-plane sapphire, splitting of the A and B excitons induced by the uniaxial in-plane stress is also observed.
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| 6. |
- Paskov, Plamen, 1959-, et al.
(author)
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Optical up-conversion processes in InAs quantum dots
- 2001
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In: Japanese Journal of Applied Physics. - 0021-4922 .- 1347-4065. ; 40:3 B, s. 2080-2083
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Journal article (peer-reviewed)abstract
- Up-converted photoluminescence (UPL) in InAs/GaAs self-assembled quantum dots (QDs) is reported. With a resonant excitation of QDs we observe an efficient emission from the GaAs barrier. The excitation spectrum of the UPL shows that the signal disappears if the excitation energy is tuned below the absorption band of the QDs. The intensity of UPL exhibits an almost quadratic dependence on the excitation intensity. The observed effect is explained by a two-step two-photon absorption process involving quantum dot states as intermediate states. ⌐ 2001 The Japan Society of Applied Physics.
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| 7. |
- Zhao, Q.X., et al.
(author)
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Dynamic properties of radiative recombination in p-type d-doped layers in GaAs
- 2001
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In: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 63
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Journal article (peer-reviewed)abstract
- We present an optical study of thin Zn-doped GaAs layers embedded in bulk GaAs, grown by metal-organic vapor-phase-epitaxy by means of stationary and time-resolved optical spectroscopy. The concentration of the Zn acceptors was aimed at 2×1020/cm3 in 4-nm-wide doping regions. The intensity of the optical radiative transition (so called the F emission) appearing in photoluminescence spectra was found to be related to holes confined at doping regions. The F emission shows a strong dependence on excitation intensity and temperature. The energy position varies from 1.46 to 1.49 eV as the excitation density changes from about 40 mW/cm2 to 23 W/cm2. The dynamic properties of the F-emission band have been studied by time-resolved spectroscopy. The F emission shows a nonexponential decay character. The decay time of the F emission exhibits a strong dependence on the detection energy within the F-emission band. The decay time becomes longer as the detection energy is redshifted.
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