| 1. |
- Ghasemi, Masoomeh, et al.
(författare)
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Assembling your nanowire : An overview of composition tuning in ternary III-V nanowires
- 2021
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 32:7
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Forskningsöversikt (refereegranskat)abstract
- The ability to grow defect-free nanowires in lattice-mismatched material systems and to design their properties has made them ideal candidates for applications in fields as diverse as nanophotonics, nanoelectronics and medicine. After studying nanostructures consisting of elemental and binary compound semiconductors, scientists turned their attention to more complex systems - ternary nanowires. Composition control is key in these nanostructures since it enables bandgap engineering. The use of different combinations of compounds and different growth methods has resulted in numerous investigations. The aim of this review is to present a survey of the material systems studied to date, and to give a brief overview of the issues tackled and the progress achieved in nanowire composition tuning. We focus on ternary III x III1-x V nanowires (AlGaAs, AlGaP, AlInP, InGaAs, GaInP and InGaSb) and IIIV x V1-x nanowires (InAsP, InAsSb, InPSb, GaAsP, GaAsSb and GaSbP).
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| 2. |
- Jafari Jam, R., et al.
(författare)
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Embedded sacrificial AlAs segments in GaAs nanowires for substrate reuse
- 2020
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Ingår i: Nanotechnology. - Bristol : Institute of Physics Publishing (IOPP). - 0957-4484 .- 1361-6528. ; 31:20
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Tidskriftsartikel (refereegranskat)abstract
- We report on the use of a sacrificial AlAs segment to enable substrate reuse for nanowire synthesis. A silicon nitride template was deposited on a p-type GaAs substrate. Then a pattern was transferred to the substrate by nanoimprint lithography and reactive ion etching. Thermal evaporation was used to define Au seed particles. Metalorganic vapour phase epitaxy was used to grow AlAs-GaAs NWs in the vapour-liquid-solid growth mode. The yield of synthesised nanowires, compared to the number expected from the patterned template, was more than 80%. After growth, the nanowires were embedded in a polymer and mechanically removed from the parent substrate. The parent substrate was then immersed in an HCl:H2O (1:1) mixture to dissolve the remaining stub of the sacrificial AlAs segment. The pattern fidelity was preserved after peeling off the nanowires and cleaning, and the semiconductor surface was flat and ready for reuse. Au seed particles were then deposited on the substrate by use of pulse electrodeposition, which was selective to the openings in the growth template, and then nanowires were regrown. The yield of regrowth was less optimal compared to the first growth but the pattern was preserved. Our results show a promising approach to reduce the final cost of III-V nanowire based solar cells. © 2020 The Author(s). Published by IOP Publishing Ltd.
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| 3. |
- Menon, Heera, et al.
(författare)
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Improved quality of InSb-on-insulator microstructures by flash annealing into melt
- 2021
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 32:16
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Tidskriftsartikel (refereegranskat)abstract
- Monolithic integration of III-V semiconductors with Silicon technology has instigated a wide range of new possibilities in the semiconductor industry, such as combination of digital circuits with optical sensing and high-frequency communication. A promising CMOS compatible integration process is rapid melt growth (RMG) that can yield high quality single crystalline material at low cost. This paper represents the study on ultra-thin InSb-on-insulator microstructures integrated on a Si platform by a RMG-like process. We utilize flash lamp annealing (FLA) to melt and recrystallize the InSb material for an ultra-short duration (milliseconds), to reduce the thermal budget necessary for integration with Si technology. We compare the result from FLA to regular rapid thermal annealing (seconds). Recrystallized InSb was characterized using electron back scatter diffraction which indicate a transition from nanocrystalline structure to a crystal structure with grain sizes exceeding 1 μm after the process. We further see a 100× improvement in electrical resistivity by FLA annealed sample when compared to the as-deposited InSb with an average Hall mobility of 3100 cm2 V−1 s−1 making this a promising step towards realizing monolithic mid-infrared detectors and quantum devices based on InSb.
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| 4. |
- Sivakumar, Sudhakar, et al.
(författare)
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Aerotaxy : gas-phase epitaxy of quasi 1D nanostructures
- 2021
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 32:2, s. 25605-25605
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Tidskriftsartikel (refereegranskat)abstract
- Cost- and resource-efficient growth is necessary for many applications of semiconductor nanowires. We here present the design, operational details and theory behind Aerotaxy, a scalable alternative technology for producing quality crystalline nanowires at a remarkably high growth rate and throughput. Using size-controlled Au seed particles and organometallic precursors, Aerotaxy can produce nanowires with perfect crystallinity and controllable dimensions, and the method is suitable to meet industrial production requirements. In this report, we explain why Aerotaxy is an efficient method for fabricating semiconductor nanowires and explain the technical aspects of our custom-built Aerotaxy system. Investigations using SEM (scanning electron microscope), TEM (transmission electron microscope) and other characterization methods are used to support the claim that Aerotaxy is indeed a scalable method capable of producing nanowires with reproducible properties. We have investigated both binary and ternary III-V semiconductor material systems like GaAs and GaAsP. In addition, common aspects of Aerotaxy nanowires deduced from experimental observations are used to validate the Aerotaxy growth model, based on a computational flow dynamics (CFD) approach. We compare the experimental results with the model behaviour to better understand Aerotaxy growth.
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| 5. |
- He, Li, et al.
(författare)
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Focused ion beam fabrication of novel core-shell nanowire structures
- 2008
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 19:44
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Tidskriftsartikel (refereegranskat)abstract
- A novel method of indirect deposition by means of a focused ion beam (FIB) is utilized to develop metal/insulator/semiconductor nanowire core-shell structures. This method is based upon depositing an annular pattern centered on a nanowire, with secondary deposition then coating the wire. Typical cross-sectional deposition area increments as a function of ion doses are 1.3 x 10(-2) mu m(2) nC(-1) for Pt and 3.5 x 10(-2) mu m(2) nC(-1) for SiO2. The structures are examined with a transmission electron microscope (TEM) using a new nanowire TEM sample preparation method that allows direct examinations of individually selected core-shell nanowires fabricated under different indirect FIB deposition conditions. Elemental analyses by means of energy dispersive x-ray spectroscopy and electron energy filtered TEM imaging verify the deposition of SiO2 and Pt layers. Relatively uniform Pt and SiO2 coatings on individual GaP nanowires can be achieved with overall thickness deviation of about 10% for deposition up to 25-30 nm thick Pt or SiO2 shells. It should be possible to extend this approach to any nanowire/nanotube system, and to a wide range of coatings in any desired layer sequences.
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| 6. |
- 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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| 7. |
- Bermeo, Marie, et al.
(författare)
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Branched-gallium phosphide nanowires seeded by palladium nanoparticles
- 2023
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Ingår i: Nanotechnology. - 0957-4484. ; 34:39
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Tidskriftsartikel (refereegranskat)abstract
- Palladium nanoparticles were produced by a chemical reagent-free and versatile method called spark ablation with control over particle size and density. These nanoparticles were used as catalytic seed particles for gallium phosphide nanowire growth by metalorganic vapour-phase epitaxy. Controlled growth of GaP nanowires using significantly small Pd nanoparticles between 10 and 40 nm diameter was achieved by varying several growth parameters. Low V/III ratios below 2.0 promote higher Ga incorporation into the Pd nanoparticles. Moderate growth temperatures under 600 °C avoid kinking and undesirable GaP surface growth. In addition, a second batch of palladium nanoparticles of concentration up to 1000 particles μm−2 was deposited onto the GaP nanowires. Subsequently, three-dimensional nanostructures evolved, with branches growing along the surface of the GaP nanowires. The GaP nanowires revealed a zinc blende structure with multiple twinning and a PdGa phase at the tip of the nanowires and branches.
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