| 1. |
- Doyle, Catherine M., et al.
(författare)
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Surface Mediated Synthesis of 2D Covalent Organic Networks : 1,3,5-Tris(4-bromophenyl)benzene on Au(111)
- 2019
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Ingår i: Physica Status Solidi (B) Basic Research. - : Wiley. - 0370-1972. ; 256:2
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Tidskriftsartikel (refereegranskat)abstract
- Covalent organic networks derived from surface-mediated self-assembly of 1,3,5-tris(4-bromophenyl)benzene into two-dimensional networks on Au(111) have been studied by scanning tunneling microscopy (STM) and by X-ray spectroscopic methods. High resolution soft X-ray photoemission spectroscopy (SXPS) using synchrotron radiation have been used to study the formation of the 1,3,5-tris(4-bromophenyl)benzene-derived 2D networks by observing temperature-dependent C 1s and Br 3d core level XPS spectra. X-ray absorption (XA) measurements of the formation of these 2D networks have been obtained at the C K-edge where their temperature and angular dependence are examined. The results of these XPS and XA spectroscopic measurements are compared to detailed ab initio electronic structure calculations of 1,3,5-tris(4-bromophenyl)benzene molecules to aid the interpretation of the features of these spectra.
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| 2. |
- Vinogradov, Nikolay A., et al.
(författare)
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Single-Phase Borophene on Ir(111) : Formation, Structure, and Decoupling from the Support
- 2019
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 13:12, s. 14511-14518
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Tidskriftsartikel (refereegranskat)abstract
- Artificial two-dimensional (2D) materials, which host electronic or spatial structure and properties not typical for their bulk allotropes, can be grown epitaxially on atomically flat surfaces; the design and investigation of these materials are thus at the forefront of current research. Here we report the formation of borophene, a planar boron allotrope, on the surface of Ir(111) by exposing it to the flux of elemental boron and consequent annealing. By means of scanning tunneling microscopy and density functional theory calculations, we reveal the complex structure of this borophene, different from all planar boron allotropes reported earlier. This structure forms as a single phase on iridium substrate in a wide range of experimental conditions and may be then decoupled from the substrate via intercalation. These findings allow for production of large, defect-free borophene sheets and advance theoretical understanding of polymorphism in borophene.
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| 3. |
- Harlow, Gary S., et al.
(författare)
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Observing growth under confinement : Sn nanopillars in porous alumina templates
- 2019
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Ingår i: Nanoscale Advances. - : Royal Society of Chemistry (RSC). - 2516-0230. ; 1:12, s. 4764-4771
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Tidskriftsartikel (refereegranskat)abstract
- Using a micro-focused high-energy X-ray beam, we have performed in situ time-resolved depth profiling during the electrochemical deposition of Sn into an ordered porous anodic alumina template. Combined with micro-diffraction we are able to follow the variation of the structure at the atomic scale as a function of depth and time. We show that Sn initially deposits at the bottom of the pores, and forms metallic nanopillars with a preferred [100] orientation and a relatively low mosaicity. The lattice strain is found to differ from previous ex situ measurements where the Sn had been removed from the porous support. The dendritic nature of the pore bottom affects the Sn growth mode and results in a variation of Sn grain size, strain and mosaicity. Such atomic scale information of nano-templated materials during electrodeposition may improve the future fabrication of devices.
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| 4. |
- Linpé, Weronica, et al.
(författare)
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The State of Electrodeposited Sn Nanopillars within Porous Anodic Alumina from In-situ X-ray Observations
- 2019
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 2:5, s. 3031-3038
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Tidskriftsartikel (refereegranskat)abstract
- Porous anodic alumina (PAA) can be used as a template for controlled electrodeposition and growth of nano-structures, it is also essential for long-lasting decorative coloring of aluminum. We have investigated the deposition of Sn nanopillars into PAA in-situ, with Grazing transmission small angle X-ray scattering, X-ray fluorescence and X-ray absorption near edge structure spectroscopy. An accumulation of Sn could be detected in the pores during the electrodeposition. From the X-ray absorption near edge structure spectroscopy measurements we could conclude that the deposited Sn was primarily in the metallic state. Ex-situ scanning electron microscopy cross-section measurements show Sn nanopillars inside the PAA.
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| 5. |
- Zakharov, Alexei, et al.
(författare)
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Wafer Scale Growth and Characterization of Edge Specific Graphene Nanoribbons for Nanoelectronics
- 2019
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 2:1, s. 156-162
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Tidskriftsartikel (refereegranskat)abstract
- One of the ways to use graphene in field effect transistors is to introduce a band gap by quantum confinement effect. That is why narrow graphene nanoribbons (GNRs) with width less than 50 nm are considered to be essential components in future graphene electronics. The growth of graphene on sidewalls of SiC(0001) mesa structures using scalable photolithography was shown to produce high quality GNRs with excellent transport properties. Such epitaxial graphene nanoribbons are very important in fundamental science but if GNRs are supposed to be used in advanced nanoelectronics, high quality thin (<50 nm) nanoribbons should be produced on a large (wafer) scale. Here we present a technique for scalable template growth of high quality GNRs on Si-face of SiC(0001) and provide detailed structural information along with transport properties. For the first time we succeeded now to avoid SiC-facet instabilities in order to grow high quality GNRs along both [11̅00] and [112̅0] crystallographic directions on the same substrate. The quality of the grown nanoribbons was confirmed by comprehensive characterization with atomic resolution STM, dark field LEEM, and transport measurements. This approach generates an entirely new platform for both fundamental and application driven research of quasi one-dimensional carbon based magnetism and spintronics.
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