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| 2. |
- Dick Thelander, Kimberly, et al.
(författare)
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Improving InAs nanotree growth with composition-controlled Au-In nanoparticles
- 2006
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 17:5, s. 1344-1350
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Tidskriftsartikel (refereegranskat)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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| 3. |
- Johansson, Jonas, et al.
(författare)
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Growth related aspects of epitaxial nanowires
- 2006
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Ingår i: Nanotechnology. - 0957-4484. ; 17:11, s. 355-361
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Tidskriftsartikel (refereegranskat)abstract
- We use metal - organic vapour phase epitaxy for growth investigations of epitaxial nanowires in III - V materials, such as GaAs, GaP, InAs, and InP. In this paper we focus on gold assisted growth of nanowires. The nature of the metal particle - whether it is in the solid or liquid state - is discussed. For InAs and InP we have demonstrated that gold assisted wires can only grow at temperatures where the particle is solid. We continue with a discussion concerning the kinetic aspects of nanowire growth. Under common growth conditions one observes that thinner wires grow faster than thicker wires, contrary to what was described in the early days of whisker growth. We address and resolve this discrepancy by discussing a simple transport model and comparing the supersaturations of different systems. Finally, we describe the morphology of epitaxial III - V nanowires with emphasis on the crystal structure.
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| 4. |
- Johansson, Jonas, et al.
(författare)
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Structural properties of (111)B-oriented III-V nanowires
- 2006
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-4660 .- 1476-1122. ; 5:7, s. 574-580
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Tidskriftsartikel (refereegranskat)abstract
- Controlled growth of nanowires is an important, emerging research field with many applications in, for example, electronics, photonics, and life sciences. Nanowires of zinc blende crystal structure, grown in the left fence111right fenceB direction, which is the favoured direction of growth, usually have a large number of twin-plane defects. Such defects limit the performance of optoelectronic nanowire-based devices. To investigate this defect formation, we examine GaP nanowires grown by metal-organic vapour-phase epitaxy. We show that the nanowire segments between the twin planes are of octahedral shape and are terminated by {111} facets, resulting in a microfaceting of the nanowires. We discuss these findings in a nucleation context, where we present an idea on how the twin planes form. This investigation contributes to the understanding of defect formation in nanowires. One future prospect of such knowledge is to determine strategies on how to control the crystallinity of nanowires.
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| 5. |
- Wacaser, Brent, et al.
(författare)
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Growth and characterization of defect free GaAs nanowires
- 2006
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Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248. ; 287:2, s. 504-508
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Tidskriftsartikel (refereegranskat)abstract
- Most III-V compound semiconductor nanowires seeded by metal particles grow preferentially in a (over bar 1 over bar 1 over bar 1)B direction (B wires) and most commonly with many stacking faults perpendicular to the growth direction. If growth proceeds in an alternate direction, defect-free growth has been observed. We present experimental results for the growth of GaAs nanowires in a previously uninvestigated growth direction, a < 111 > A direction (A wires). One novelty is that a {111} A growth plane, like a {over bar 1 over bar 1 over bar 1} B, is a close packed plane where the stacking sequence can be interrupted forming stacking faults, but unlike the B wires the A wires lack stacking faults. It is also observed that, when grown under equivalent conditions, the growth rate of the A wires is approximately twice that of the B wires. Additionally, B wires have a hexagonal cross section with three {11 over bar 2} and three {11 over bar 2} side facets. A wires, on the other hand, have only three major side facets which are of the {11 over bar 2} type, giving them a triangular cross section. (c) 2005 Elsevier B.V. All rights reserved.
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