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| 2. |
- Adnane, Bouchaib, et al.
(författare)
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Mid/far-infrared detection using a MESFET with B-modulation doped Ge-dot/SiGe-well multiple stacks in the channel region
- 2004
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Konferensbidrag (refereegranskat)abstract
- Multiple modulation-doped Ge-dot/SiGe-QW stack structures were grown using MBE, and processed as FET devices for mid/far infrared detection. From a non-optimized device, a broadband photoresponse has been observed in the mid-infrared range of 3-15 μm. A peak responsivity was estimated to be as high as 100 mA/W at T= 20 K. This work indicates that SiGE QD/QW structures using the lateral transport geometry can be a potential candidate for photodetectors operating in far-infrared range.
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| 3. |
- Ferdos, Fariba, 1966, et al.
(författare)
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Influence of a thin GaAs cap layer on structural and optical properties of InAs quantum dots
- 2002
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 81:7, s. 1195-7
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Tidskriftsartikel (refereegranskat)abstract
- In this letter we investigate the changes in the surface morphology and emission wavelength of InAs quantum dots (QDs) during initial GaAs encapsulation by atomic force microscopy and photoluminescence. The density (2.9×1010 cm-2) and height (7.9±0.4 nm) of the uncapped QDs decrease and saturate at 0.6×1010 cm-2 and 4 nm, respectively, after the deposition of 4 monolayers (MLs) of GaAs. A model for the evolution of surface morphology is proposed. Photoluminescence spectra of the surface dots show a wavelength shift from 1.58 to 1.22 ?m when the GaAs capping layer thickness increases from 0 to 8 MLs.
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| 4. |
- Ferdos, Fariba, 1966, et al.
(författare)
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Influence of initial GaAs and AlAs cap layers on InAs quantum dots grown by molecular beam epitaxy
- 2003
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Ingår i: Journal of Crystal Growth. - 0022-0248. ; 251:1-4, s. 145-9
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Tidskriftsartikel (refereegranskat)abstract
- Capping of InAs quantum dots (QDs) with AlAs or GaAs causes a significant change in the structural properties of the QDs. However, there is a basic difference between these two capping materials. The GaAs capping causes a dramatic reduction of the dot density and height. AlAs capping, on the other hand, results in a partly suppressed height reduction and a higher dot density.
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| 5. |
- Ferdos, Fariba, 1966, et al.
(författare)
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Influence of thin GaAs and AlAs cap layers on the structural properties of InAs quantum dots grown by molecular beam epitaxy
- 2002
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Ingår i: International Conference on Molecular Beam Epitaxy, 2002. ; , s. 285-6
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Konferensbidrag (refereegranskat)abstract
- Self-organised InAs quantum dots (QDs) are used as optical gain material in long wavelength lasers on GaAs. The measured QD height and density are often used as figures of merits, and great efforts have been made to maximise these two parameters to extend the wavelength coverage. In this work, we investigate the influence of initial GaAs and AlAs cap layers on the structural properties of InAs QDs. The study clearly shows that capping of InAs QDs causes a strong modification of not only the QD shape and height but also the QD density
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| 9. |
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| 10. |
- Willander, Magnus, et al.
(författare)
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Optical properties of InAs quantum dots
- 2002
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Ingår i: Acta Physica Polonica. A. - : Polish Academy of Sciences Warsaw. - 0587-4246 .- 1898-794X. ; 102:4-5, s. 567-576
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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