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| 2. |
- Chen, Jianing, et al.
(författare)
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Surface-enhanced Raman scattering of rhodamine 6G on nanowire arrays decorated with gold nanoparticles
- 2008
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 19:27, s. 5-275712
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the surface-enhanced Raman scattering (SERS) of rhodamine 6G (R6G) adsorbed on Au nanoparticles attached to InP nanowires. We find that nanowire arrays act as frameworks for effective SERS substrates with a significantly higher Raman signal sensitivity than a planar framework of Au nanoparticles adsorbed two-dimensionally on a flat surface. The SERS signal displays a clear polarization-dependent effect when the nanowires are arranged in a row. We also find that the SERS signal increases with time during continuous laser illumination. The plasmon-enhanced optical forces between Au nanoparticles may either move pairs of nanoparticles closer together or attract adsorbed molecules by moving them to the junctions of Au nanoparticle aggregates. Such effects by plasmon optical forces may cause the observed increase of the SERS signal with continuous laser illumination.
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| 3. |
- Deppert, Knut, et al.
(författare)
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Epitaxielle Kristallnadeln und -bäume
- 2005
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Ingår i: Book of abstracts: DGKK-Jahrestagung, Köln, Germany (2005).
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 4. |
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| 5. |
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| 6. |
- Dick Thelander, Kimberly, et al.
(författare)
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Failure of the vapor-liquid-solid mechanism in Au-assisted MOVPE growth of InAs nanowires
- 2005
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 5:4, s. 761-764
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Tidskriftsartikel (refereegranskat)abstract
- We report the temperature dependence of the Au-assisted growth of InAs nanowires in MOVPE. Extensive studies of the growth of such nanowires have attributed growth to the so-called vapor-liquid-solid (VLS) mechanism, with a liquid Au-In alloy particle. We assert here that growth is instead assisted by a solid particle and does not occur at all when the particle is a liquid. Thus the temperature range of InAs nanowire growth is limited by the melting of the Au-In alloy. Comparison with growth of InAs nanowires in the same system assisted by a layer of SiOx is used to support this conclusion.
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| 7. |
- Dick Thelander, Kimberly, et al.
(författare)
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Self-assembled InAs nanowire networks
- 2005
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Ingår i: Book of extended abstracts: MRS Fall Meet, Boston, Ma, USA, 2005.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Granroth, Sari, et al.
(författare)
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Investigation of interface properties of Ni/Cu multilayers by high kinetic energy photoelectron spectroscopy
- 2009
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121 .- 1550-235X. ; 80:9
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Tidskriftsartikel (refereegranskat)abstract
- High kinetic-energy photoelectron spectroscopy (HIKE) or hard x-ray photoelectron spectroscopy has been used to investigate the alloying of Ni/Cu (100) multilayers. Relative intensities of the corelevels and their chemical shifts derived from binding energy changes are shown to give precise information on physicochemical properties and quality of the buried layers. Interface roughening, including kinetic properties such as the rate of alloying, and temperature effects on the processes can be analyzed quantitatively. Using HIKE, we have been able to precisely follow the deterioration of the multilayer structure at the atomic scale and observe the diffusion of the capping layer into the multilayer structure which in turn is found to lead to a segregation in the ternary system. This is of great importance for future research on multilayered systems of this kind. Our experimental data are supplemented by first-principles theoretical calculations of the core-level shifts for a ternary alloy to allow for modeling of the influence of capping materials on the chemical shifts.
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| 9. |
- 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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| 10. |
- Johansson, Jonas, et al.
(författare)
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The structure of <1 1 1 > B oriented GaP nanowires
- 2007
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Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248. ; 298, s. 635-639
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Tidskriftsartikel (refereegranskat)abstract
- Nanowires of zinc blende crystal structure, grown in the < 111 > B direction usually have a large number of twin plane defects. In order to investigate this phenomenon, we grow GaP nanowires with metal-organic vapor phase epitaxy. By rotating the nanowires in a high resolution transmission electron microscope, we show that the nanowire segments between the twin planes are of octahedral shape and are terminated by {111} facets. Due to the alternating orientations of these twin octahedra, the sidewalls of the nanowires can be described as microfaceted surfaces with an overall orientation of 11 1 2}, but composed of alternating 11 1 I}A and {1 I 1}B facets. Moreover, the segment thicknesses follow exponential distributions, which show that there is a certain probability of twin plane formation, which is independent of segment thickness. (c) 2006 Elsevier B.V. All rights reserved.
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