Research: Radial organic/inorganic superlattices
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A radial InGaAs/GaAs/alcanethiolate superlattice has been fabricated by the roll‑up of a strained InGaAs/GaAs bilayer
functionalized with a thiol-based molecular self-assembled monolayer (SAM). The technique allows the controlled formation of multi‑period inorganic/organic hybrid heterostructures. The InGaAs/GaAs bilayer was grown by molecular beam epitaxy (MBE) on an AlAs release layer on a GaAs substrate. A monolayer of 1‑hexadecanethiol was allowed to self‑assemble from solution on the surface of the epitaxial GaAs film. The InGaAs/GaAs/SAM trilayer was then released by selectively etching away the AlAs. The strain in the epitaxial bilayer causes the released inorganic/organic trilayer to roll up into a nanotube. The tube diameter depends on the amount of strain which is controlled by the thickness of the epitaxial films. The tubes can perform several rotations on the surface, depending on the duration of the release etch. Thin cross‑sections of the nanotubes were prepared by focused ion beam etching and studied by high-resolution transmission electron microscopy and energy-dispersive x‑ray analysis, revealing a tightly wound superlattice composed of alternating single-crystalline inorganic heterostructures and organic monolayers with high‑quality interfaces and no oxygen contamination or amorphization of the inorganic films. Institute for Integrative Nanosciences (Oliver G. Schmidt) Back to Research |
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