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Physical states in nanoscale solids are tied to their crystalline order, morphology, and size. However, deterministically accessing different nanocrystal morphologies from a single phase usually involves complex synthetic routes, catalysts, or multi-step lithographic techniques. Here, we demonstrate the catalyst-free synthesis of nanosheets and nanowires based on the luminescent 2D van der Waals (vdW) phase, GaTe, as a model phase that manifests atomic precision and a highly anisotropic quasi-1D substructure. We program the size and morphology of the resulting nanostructures by varying the relative rates of precursor deposition and diffusion, achieving dense, uniform, and widespread growth. Ultrathin nanowires resulting from this synthesis exhibit strikingly enhanced low-temperature luminescence with narrow near-infrared (NIR) emission bandwidths. These spectral characteristics arise from defect-bound states confined within a nanowire morphology that acts as a deep sub-wavelength optical cavity, making them suitable as optical emitters with small footprints either as stand-alone structures or coupled with other vdW crystals.
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High yield production of ultrathin fibroid semiconducting nanowire of Ta2Pd3Se8
Immediately after the demonstration of the high-quality electronic properties in various two dimensional (2D) van der Waals (vdW) crystals fabricated with mechanical exfoliation, many methods have been reported to explore and control large scale fabrications. Comparing with recent advancements in fabricating 2D atomic layered crystals, large scale production of one dimensional (1D) nanowires with thickness approaching molecular or atomic level still remains stagnant. Here, we demonstrate the high yield production of a 1D vdW material, semiconducting Ta2Pd3Se8 nanowires, by means of liquid-phase exfoliation. The thinnest nanowire we have readily achieved is around 1 nm, corresponding to a bundle of one or two molecular ribbons. Transmission electron microscopy (TEM) and transport measurements reveal the as-fabricated Ta2Pd3Se8 nanowires exhibit unexpected high crystallinity and chemical stability. Our low-frequency Raman spectroscopy reveals clear evidence of the existing of weak inter-ribbon bindings. The fabricated nanowire transistors exhibit high switching performance and promising applications for photodetectors.
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- Award ID(s):
- 1752997
- PAR ID:
- 10158843
- Date Published:
- Journal Name:
- Nano Research
- ISSN:
- 1998-0124
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s12274-020-2784-y
