| 1. |
- Harberts, Jann, et al.
(författare)
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Culturing and patch clamping of Jurkat T cells and neurons on Al 2 O 3 coated nanowire arrays of altered morphology
- 2019
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 9:20, s. 11194-11201
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Tidskriftsartikel (refereegranskat)abstract
- Nanowire substrates play an increasingly important role for cell cultures as an approach for hybrid bio-semiconductor junctions. We investigate Jurkat T cells and neurons from mice cultured on Al 2 O 3 coated ordered and randomly distributed nanowires. Cell viability was examined by life/membrane staining reporting comparable viability on planar and nanowire substrates. Imaging the hybrid interface reveals a wrapping of the cell membrane around the very nanowire tip. Patch clamp recordings show similar electrophysiological responses on each type of nanowires compared to planar control substrates. We demonstrate that the morphological characteristic of the nanowire substrate plays a subordinate role which opens up the arena for a large range of nanowire substrates in a functionalized application such as stimulation or sensing.
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| 2. |
- Kaline P., Furlan
(författare)
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Photonic materials for high-temperature applications: Synthesis and characterization by X-ray ptychographic tomography
- 2018
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Ingår i: Applied Materials Today. - : Elsevier BV. - 2352-9407. ; 13, s. 359-369
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Tidskriftsartikel (refereegranskat)abstract
- Photonic materials for high-temperature applications need to withstand temperatures usually higher than 1000 °C, whilst keeping their function. When exposed to high temperatures, such nanostructured materials are prone to detrimental morphological changes, however the structure evolution pathway of photonic materials and its correlation with the loss of material's function is not yet fully understood. Here we use high-resolution ptychographic X-ray computed tomography (PXCT) and scanning electron microscopy (SEM) to investigate the structural changes in mullite inverse opal photonic crystals produced by a very-low-temperature (95 °C) atomic layer deposition (ALD) super-cycle process. The 3D structural changes caused by the high-temperature exposure were quantified and associated with the distinct structural features of the ceramic photonic crystals. Other than observed in photonic crystals produced via powder colloidal suspensions or sol-gel infiltration, at high temperatures of 1400 °C we detected a mass transport direction from the nano pores to the shells. We relate these different structure evolution pathways to the presence of hollow vertexes in our ALD-based inverse opal photonic crystals. Although the periodically ordered structure is distorted after sintering, the mullite inverse opal photonic crystal presents a photonic stopgap even after heat treatment at 1400 °C for 100 h.
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| 3. |
- Gooth, Johannes, et al.
(författare)
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Local Magnetic Suppression of Topological Surface States in Bi2Te3 Nanowires
- 2016
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Ingår i: ACS Nano. - Washington : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 10:7, s. 7180-7188
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Tidskriftsartikel (refereegranskat)abstract
- Locally induced, magnetic order on the surface of a topological insulator nanowire could enable room-temperature topological quantum devices. Here we report on the realization of selective magnetic control over topological surface states on a single facet of a rectangular Bi2Te3 nanowire via a magnetic insulating Fe3O4 substrate. Low-temperature magnetotransport studies provide evidence for local time-reversal symmetry breaking and for enhanced gapping of the interfacial 1D energy spectrum by perpendicular magnetic-field components, leaving the remaining nanowire facets unaffected. Our results open up great opportunities for development of dissipation-less electronics and spintronics.
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| 4. |
- Gooth, Johannes, et al.
(författare)
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Thermoelectric performance of classical topological insulator nanowires
- 2015
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 0268-1242 .- 1361-6641. ; 30:1
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Tidskriftsartikel (refereegranskat)abstract
- There is currently substantial effort being invested into creating efficient thermoelectric (TE) nanowires based on topological insulator (TI) chalcogenide-type materials. A key premise of these efforts is the assumption that the generally good TE properties that these materials exhibit in bulk form will translate into similarly good or even better TE performance of the same materials in nanowire form. Here, we calculate TE performance of TI nanowires based on Bi2Te3, Sb2Te3 and Bi2Se3 as a function of diameter and Fermi level. We show that the TE performance of TI nanowires does not derive from the properties of the bulk material in a straightforward way. For all investigated systems the competition between surface states and bulk channel causes a significant modification of the TE transport coefficients if the diameter is reduced into the sub 10 mu m range. Key aspects are that the surface and bulk states are optimized at different Fermi levels or have different polarity as well as the high surface to volume ratio of the nanowires. This limits the maximum TE performance of TI nanowires and thus their application in efficient TE devices.
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