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| 2. |
- Deppert, Knut, et al.
(författare)
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Aerosol fabrication of nanocrystals of InP
- 1999
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Ingår i: 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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Tidskriftsartikel (refereegranskat)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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| 3. |
- Deppert, Knut, et al.
(författare)
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Feasibility study of nanoparticle synthesis from powders of compounds with incongruent sublimation behavior by the evaporation/condensation method
- 1998
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Ingår i: Nanostructured Materials. - 0965-9773. ; 10:4, s. 565-573
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we investigate the feasibility of a fabrication route to produce nanocrystals of compound material with incongruent sublimation behavior via the simple evaporation of the powder of the compound. The generation of stoichiometric particles would only be possible if the particle formation occurs at temperatures below the incongruent sublimation point. Our experiments, done on three different III-V compounds, show that the simple evaporation of the powder of those materials to obtain stoichiometric particles is not possible. Particle formation does not start at temperatures below the incongruent sublimation point. Particles synthesized consisted not of the compound but almost entirely of the more volatile group-Velement, leading to a change in the composition of the source material and thus to irreproducible behavior.
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| 4. |
- Deppert, Knut, et al.
(författare)
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Size-selected nanocrystals of III-V semiconductor materials by the aerotaxy method
- 1998
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Ingår i: Journal of Aerosol Science. - 0021-8502. ; 29:5-6, s. 737-748
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Tidskriftsartikel (refereegranskat)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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| 5. |
- Junno, Tobias, et al.
(författare)
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Single-electron devices via controlled assembly of designed nanoparticles
- 1999
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Ingår i: Microelectronic Engineering. - 0167-9317. ; 47:1-4, s. 179-183
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Magnusson, Martin H., et al.
(författare)
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Gold nanoparticles : Production, reshaping, and thermal charging
- 1999
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Ingår i: Journal of Nanoparticle Research. - 1388-0764. ; 1:2, s. 243-251
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Tidskriftsartikel (refereegranskat)abstract
- Gold nanoparticles are of great interest for various nanoelectronic applications, e.g., for making single electron transistors or very fine leads to molecular size entities. For this and other applications, it is important that all particles have controllable size and shape. In this paper, we describe the production of size-selected gold aerosol particles in the 20 nm range made by evaporation in a high-temperature tube furnace and subsequent size selection. To obtain spherical particles, it was necessary to reshape the particles at high temperature, which was investigated for temperatures between 25°C and 1200°C. High-resolution transmission electron microscopy showed that the degree of crystallinity became higher for higher reshaping temperature. During reshaping at high temperature, an anomalous charging behavior was discovered, whereby negatively as well as positively charged particles became multiply negatively charged. Possible mechanisms for explaining this thermally activated phenomenon are discussed.
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