| 1. |
- Borgström, Magnus, et al.
(författare)
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InAs quantum dots grown on InAlGaAs lattice matched to InP
- 2003
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Ingår i: Journal of Crystal Growth. - 0022-0248. ; 252:4, s. 481-485
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present InAs quantum dots prepared on an InxAlyGa1-x-yAs surface by metal organic vapor phase epitaxy. Atomic force microscopy measurements indicate that dots grown on material with higher Al content are smaller, and that the local dot densities on step-bunched facets formed on the vicinal (0 0 1) surfaces increase. We find that these dots show luminescence at very long wavelengths, lambda(room temperature) approximate to 2.1 mum, and that the emission wavelengths are blue-shifted when the Al content is increased in the layer onto which dot material is deposited. (C) 2003 Elsevier Science B.V. All rights reserved.
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| 2. |
- Borgström, Magnus, et al.
(författare)
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Site control of InAs quantum dots on a patterned InP surface: As/P exchange reactions
- 2003
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Ingår i: Journal of Crystal Growth. - 0022-0248. ; 248, s. 310-316
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Tidskriftsartikel (refereegranskat)abstract
- In this paper. we present the effect of annealing temperature and annealing time on InAs site-controlled quantum dot growth. Individual InAs quantum dots formed by self-assembling have been positioned into holes, created by partial overgrowth of electron beam induced nano-carbon deposits by metal organic vapor phase epitaxy. As/P exchange reactions produce material sufficient for selective dot nucleation in the holes. Results. showing that As/P exchange reactions occur even when capping the dots with InP are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 3. |
- 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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| 4. |
- Ferdos, Fariba, 1966, et al.
(författare)
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Optimisation of MBE growth conditions for InAs quantum dots on (001) GaAs for 1.3 μm luminescence
- 2001
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Ingår i: Journal of Crystal Growth. - 0022-0248. ; 227-228, s. 1140-5
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Tidskriftsartikel (refereegranskat)abstract
- We present a study of the optimised growth conditions for InAs quantum dots (QDs) grown on GaAs substrates by solid source molecular beam epitaxy (SSMBE). Growth conditions for best luminescence intensity and linewidth were found within narrow windows of substrate temperature (500-520°C) and nominal InAs layer thickness (3.3-3.7 monolayers). The emission wavelength of such InAs QDs capped by GaAs was around 1.24 ?m. However, this is redshifted to 1.3 ?m or more by capping the InAs QDs with a thin layer of InxGa1-xAs. The results show that both In content and thickness of the capping layer can be used to tune the emission wavelength. Atomic force microscopy images show that the surface recovers to two-dimensional when depositing In0.2Ga0.8As while remaining three-dimensional when depositing In0.4Ga0.6As.
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| 5. |
- Johansson, Jonas, et al.
(författare)
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Kinetics of self-assembled island formation: Part I - Island density
- 2002
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Ingår i: Journal of Crystal Growth. - 0022-0248. ; 234:1, s. 132-138
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Tidskriftsartikel (refereegranskat)abstract
- We present a rate equation model for self-assembled quantum dot formation, or Stranski-Krastanow growth. The model includes a kinetically defined critical wetting layer thickness and a subsequent wetting layer decomposition. With these rate equations, total island densities can be calculated under varying deposition conditions, i.e., temperature and deposition rate.
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| 6. |
- Johansson, Jonas, et al.
(författare)
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Kinetics of self-assembled island formation: Part II - Island size
- 2002
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Ingår i: Journal of Crystal Growth. - 0022-0248. ; 234:1, s. 139-144
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we propose a simple and intuitive way to predict self-assembled island sizes for varying deposition conditions, i.e., temperature and deposition rate. The average island size and the modality of the size distribution (unimodal with large or small islands, or bimodal) is calculated via materials balancing over a total island density (known by experiments or from nucleation calculations). We also find that there is a density interval in which the size distribution is bimodal. The width of this interval increases with the total amount of material in the islands. The borders of the interval change with the sizes of the small and large islands, which can also change the interval width. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 7. |
- Sass, T, et al.
(författare)
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Strain in GaP/GaAs and GaAs/GaP resonant tunnelling heterostructures
- 2003
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Ingår i: Journal of Crystal Growth. - 0022-0248. ; 248, s. 375-379
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Tidskriftsartikel (refereegranskat)abstract
- We studied the morphology of GaP/(001)GaAs and GaAs/(001)GaP heterostructures grown by metal-organic vapour-phase epitaxy and found wire-like surface undulations elongated in the [110] direction. We attribute this elongation to anisotropic lateral growth rates in the [110] and [110] directions, which are due to a different roughness of monolayer surface steps. In III-V materials grown by molecular beam epitaxy. such surface corrugations are usually elongated in [110]. We explain this difference by the two growth methods having inverted ratios of lateral growth rates in [110] and [110]. Resonant tunnelling diodes fabricated from the GaP/GaAs heterostructures showed very symmetric I-V characteristics. Their peak-to-valley ratio was limited to 2. most probably due to the corrugation of the GaP barriers. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 8. |
- Baskar, K., et al.
(författare)
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Surface morphology and localised states of GaInNAs single quantum wells grown by MOVPE
- 2003
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Ingår i: Journal of Crystal Growth. - 0022-0248 .- 1873-5002. ; 248, s. 431-436
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Tidskriftsartikel (refereegranskat)abstract
- GaInNAs/GaAs single quantum wells (QWs) have been grown by metalorganic vapour phase epitaxy (MOVPE). The surface morphology has been studied by atomic force microscopy (AFM). The density of pits observed on the surface of QW structures was found to depend on the growth temperature and dimethylhydrazine (DMHy) flow. Cross-sectional AFM image showed the presence of defects at the interface of GaInNAs/GaAs. The low temperature photoluminescence characteristics of the QWs as a function of growth temperature. DMHy flow and density of surface pits have been discussed. The origin of pit formation is addressed based on the pyrolysis products present during the growth of QWs. The results suggest that higher growth temperature maybe desirable to obtain good quality GaInNAs QWS.
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| 9. |
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| 10. |
- Danielsson, Örjan, 1973-, et al.
(författare)
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Growth rate predictions of chemical vapor deposited silicon carbide epitaxial layers
- 2002
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Ingår i: Journal of Crystal Growth. - : Elsevier. - 0022-0248 .- 1873-5002. ; 243:1, s. 170-184
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Tidskriftsartikel (refereegranskat)abstract
- Complete 3D simulations of a silicon carbide chemical vapor deposition (CVD) reactor, including inductive heating and fluid dynamics as well as gas phase and surface chemistry, have been performed. For the validation of simulated results, growth was conducted in a horizontal hot-wall CVD reactor operating at 1600°C, using SiH4 and C3H8 as precursor gases. Simulations were performed for an experimental hot-wall CVD reactor, but the results are applicable to any reactor configuration since no adjustable parameters were used to fit experimental data. The simulated results obtained are in very good agreement with experimental values. It is shown that including etching and parasitic growth on all reactor walls exposed to the gas greatly improves the accuracy of the simulations. © 2002 Elsevier Science B.V. All rights reserved.
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