| 1. |
- Fröberg, Linus, et al.
(författare)
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Transients in the Formation of Nanowire Heterostructures.
- 2008
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 8:11, s. 3815-3818
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Tidskriftsartikel (refereegranskat)abstract
- We present results on the effect of seed particle reconfiguration on the growth of short InAs and InP nanowire segments. The reconfiguration originates in two different steady state alloy compositions of the Au/In seed particle during growth of InAs and InP. From compositional analysis of the seed particle, the In content in the seed particle is determined to be 34 and 44% during InAs and InP growth, respectively. When switching between growing InAs and InP, transient effects dominate during the time period of seed particle reconfiguration. We developed a model that quantitatively explains the effect and with the added understanding we are now able to grow short period (<10 nm) nanowire superlattices.
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| 2. |
- Johansson, Jonas, et al.
(författare)
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Effects of growth conditions on the crystal structure of gold-seeded GaP nanowires
- 2008
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Ingår i: Journal of Chrystal Growth. - : Elsevier BV. - 0022-0248. ; 310:23, s. 5102-5105
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Konferensbidrag (refereegranskat)abstract
- we present results that provide fundamental insights on how to experimentally tailor the planar defect density and even the crystal structure in III-V metal-particle-seeded nanowires, where zinc blende is the stable bulk crystal structure. We have grown GaP nanowires with metal-organic vapor-phase epitaxy under different conditions: pulsing of the Ga source, and Continuous growth with and without In background. The dominant crystal structure of the nanowires is zinc blende, which when grown under continuous conditions has a high density of twin planes perpendicular to the growth direction. Using pulsed growth we observed that the twin plane separations were much longer than those observed for continuous growth with an In background. On the other hand, during continuous growth, under In-free conditions, a considerable amount of the wurtzite-phase forms. Our results suggest that it might be possible to predict the conditions necessary for the growth of wires with perfect crystal structure. We interpret our results in terms of the supersaturation during growth. (C) 2008 Elsevier B.V. All rights reserved.
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| 3. |
- Karlsson, L. S., et al.
(författare)
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Structural Characterisation of GaP <111 > B Nanowires by HRTEM
- 2008
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Ingår i: Microscopy of Semiconducting Material 2007. - 0930-8989. - 9781402086144 ; 120, s. 229-232
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Konferensbidrag (refereegranskat)abstract
- GaP < 111 > B nanowires are dominated by (111) twins orthogonal to the growth direction and show well-developed {111} side-facets. Based on this, a 3D-model has been constructed with a cross-section of an octahedron used as a building block. The twins can be of ortho- or para type i.e. by 60 degrees about the growth axis or 180 degrees in the twin plane. The segment thickness variation follows an exponential distribution with a clear dependence oil growth ternperature. Multislice simulations show different features of the twin types that are useful for further characterisation.
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| 4. |
- Molhave, Kristian, et al.
(författare)
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Epitaxial Integration of Nanowires in Microsystems by Local Micrometer-Scale Vapor-Phase Epitaxy
- 2008
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Ingår i: Small. - : Wiley. - 1613-6829 .- 1613-6810. ; 4:10, s. 1741-1746
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Tidskriftsartikel (refereegranskat)abstract
- Free-standing epitaxially grown nanowires provide a controlled growth system and an optimal interface to the underlying substrate for advanced optical, electrical, and mechanical nanowire device connections. Nanowires can be grown by vapor-phase epitaxy (VPE) methods such as chemical vapor deposition (CVD) or metal organic VPE (MOVPE). However, VPE of semiconducting nanowires is not compatible with several microfabrication processes due to the high synthesis temperatures and issues such as cross-contamination interfering with the intended microsystem or the VPE process. By selectively heating a small microfabricated heater, growth of nanowires can be achieved locally without heating the entire microsystem, thereby reducing the compatibility problems. The first demonstration of epitaxial growth of silicon nanowires by this method is presented and shows that the microsystem can be used for rapid optimization of VPE conditions. The important issue of the cross-contamination of other parts of the microsystem caused by the local growth of nanowires is also investigated by growth of GaN near previously grown silicon nanowires. The design of the cantilever heaters makes it possible to study the grown nanowires with a transmission electron microscope without sample preparation.
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