| 1. |
- Deppert, Knut, et al.
(author)
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Aerosol fabrication of nanocrystals of InP
- 1999
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In: Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers. - 0021-4922. ; 38:2 B, s. 1056-1059
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Journal article (peer-reviewed)abstract
- Nanocrystals of indium phosphide, with diameters of around 10nm, have been produced via an aerosol route. The method is based on the formation of monodisperse indium droplets and the subsequent reaction with phosphine at elevated temperature. The size of the final InP nanocrystal is self-limited by the size of the introduced size-selected In droplet. This size can be tuned carefully, thus this method allows a narrow size distribution of the nanocrystals. The kinetics of the reaction of In to produce InP depends on the temperature and the phosphine flow. Extensive high resolution transmission electron microscopy studies lead to a consistent picture of the process. Our approach opens the possibility for efficient production of size-selected semiconductor nanocrystals and it will allow new types of self-assembly and control of quantum dots.
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| 2. |
- Deppert, Knut, et al.
(author)
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Size-selected nanocrystals of III-V semiconductor materials by the aerotaxy method
- 1998
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In: Journal of Aerosol Science. - 0021-8502. ; 29:5-6, s. 737-748
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Journal article (peer-reviewed)abstract
- In this paper we present a fabrication route to produce size-selected III-V semiconductor nanocrystals via a simple, reliable, and efficient aerosol route. Since this approach includes the reaction of aerosol particles and a self-organized growth of a new compound, all in the aerosol phase, we call this process aerotaxy. Size-selected nanocrystals of different III-V compounds in a diameter range below 20 nm were fabricated using this method. Through the reaction of arsine with gallium droplets or of phosphine with indium droplets, GaAs and InP clusters were formed. Our approach opens the possibility to produce contamination-free and size-selected nanocrystals of compound semiconductor materials with considerable freedom in composition and size.
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| 3. |
- Dick Thelander, Kimberly, et al.
(author)
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Improving InAs nanotree growth with composition-controlled Au-In nanoparticles
- 2006
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In: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 17:5, s. 1344-1350
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Journal article (peer-reviewed)abstract
- Au nanoparticles are commonly used as seeds for epitaxial growth of III-V semiconductor nanowires. However, the interaction between Au and In-containing III-V materials makes it difficult to control the growth of more complex nanowire structures in materials such as InAs. Here we report the growth of InAs nanowires and branched nanotrees using Au and Au-In nanoparticles. We show that the initial composition of the particle does not affect the morphology of the first-generation nanowires, nor does it affect the final composition of the particle after growth. However, when the Au-In particles were used to seed a second generation of nanowires, producing nanotrees, the branches exhibited a 2-3 times higher growth rate and more regular shape than those seeded by pure Au particles. This result is attributed to the decreased interaction between the seed particle and the trunk nanowires when Au-In particles are used. Thus the incorporation of In into the seed particle during particle production allows for modification of the particle-wire interaction.
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| 4. |
- Dick Thelander, Kimberly, et al.
(author)
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Self-assembled InAs nanowire networks
- 2005
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In: Book of extended abstracts: MRS Fall Meet, Boston, Ma, USA, 2005.
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Conference paper (other academic/artistic)
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| 5. |
- Geretovszky, Zsolt, et al.
(author)
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Aerosol phase generation of In-Se nanoparticles
- 2006
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In: Journal of Nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880. ; 6:3, s. 600-611
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Journal article (peer-reviewed)abstract
- Results on the generation and heat treatment of In-Se nanoparticles, made by heterogeneous condensation of selenium on indium nanoparticles synthesised via the evaporation/condensation route are reported. In-situ aerosol measurements are complemented with ex-situ analysis, to provide structural, morphological, and compositional information on the In-Se nanoparticles. Our results indicate that prior to heat treatment In-Se nanoparticles have a shape in the aerosol phase, similar to an asymmetric dumbbell. The bigger particle of the dumbbell structure is made up of amorphous Se, while the overall composition of the polycrystalline smaller particle is around InSe. The smaller particle has an intrinsic structure, and consists of different InSe-compounds, with a decreasing In content towards the shell. The shape of the In-Se nanoparticles is different in the aerosol phase and on the surface of the samples. The observed variety of particle sizes and shapes on the sample surface is shown to be partly due to the agglomeration of the aerosol phase binaries (i.e., dumbbells) via coalescence on the surface of the sample and wetting of the sample surface by the Se nanoparticles. These processes make the bigger particle of the dumbbell structure appear almost perfectly hemispherical on the sample surfaces. During heat treatment at lower temperatures mainly the evaporative removal of the big Se particle of the dumbbell structure will take place. Annealing of the smaller particles starts to dominate at temperatures above 240 degrees C and makes the composition of the small particles closer to that of the thermodynamically most favoured In2Se3.
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| 6. |
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| 7. |
- Junno, Tobias, et al.
(author)
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Single-electron devices via controlled assembly of designed nanoparticles
- 1999
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In: Microelectronic Engineering. - 0167-9317. ; 47:1-4, s. 179-183
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Journal article (peer-reviewed)abstract
- Single-electron transistors (SET) rely for their functionality on extreme control of lithography and lateral positioning as well as of properties of the building blocks from which the devices are built. By an aerosol-based nanoparticle fabrication we can prepare nanocrystals down to sub-10nm dimensions with metallic or semiconducting character, as well as having a core + shell design for definition of tunnel-gaps. We present here results for a type of device that is based on the possibility to design functionality in the internal structure of the nanoparticles which are used as building blocks. We use such pre-fabricated building blocks to construct coulomb blockade devices and show that they operate at temperatures above 150K.
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| 8. |
- Karlsson, Lisa, et al.
(author)
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Crystal structure of branched epitaxial III-V nanotrees
- 2006
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In: Nano. - 1793-2920. ; 1:2, s. 139-151
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Journal article (peer-reviewed)abstract
- In this review we discuss the morphology and crystal structure of branched epitaxial III-V semiconductor structures, so called nanotrees, based on our own work with GaP, InAs and GaP/InP. These structures are formed by epitaxial growth in a step-wise procedure where each level can be individually controlled in terms of diameter, length and composition. Poly-typism is commonly observed for III-Vs with zinc blende, wurtzite or combinations thereof as the resulting crystal structure. Here we review GaP as an example of zinc blende and InAs of wurtzite type of growth in terms of nanotrees with two to three levels of growth. Included are also previously unpublished results on the growth of GaP/InP nanotrees to demonstrate effects of heteroepitaxial growth with substantial mismatch. For these structures a topotaxial growth behavior was observed with InP wires crawling along or spiraling around the GaP nanowires acting as a free-standing substrates.
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| 10. |
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