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Abstract The ongoing reduction in transistor sizes drives advancements in information technology. However, as transistors shrink to the nanometer scale, surface and edge states begin to constrain their performance. 2D semiconductors like transition metal dichalcogenides (TMDs) have dangling‐bond‐free surfaces, hence achieving minimal surface states. Nonetheless, edge state disorder still limits the performance of width‐scaled 2D transistors. This work demonstrates a facile edge passivation method to enhance the electrical properties of monolayer WSe2nanoribbons, by combining scanning transmission electron microscopy, optical spectroscopy, and field‐effect transistor (FET) transport measurements. Monolayer WSe2nanoribbons are passivated with amorphous WOxSeyat the edges, which is achieved using nanolithography and a controlled remote O2plasma process. The same nanoribbons, with and without edge passivation are sequentially fabricated and measured. The passivated‐edge nanoribbon FETs exhibit 10 ± 6 times higher field‐effect mobility than the open‐edge nanoribbon FETs, which are characterized with dangling bonds at the edges. WOxSeyedge passivation minimizes edge disorder and enhances the material quality of WSe2nanoribbons. Owing to its simplicity and effectiveness, oxidation‐based edge passivation could become a turnkey manufacturing solution for TMD nanoribbons in beyond‐silicon electronics and optoelectronics.
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Coherent X-ray measurement of step-flow propagation during growth on polycrystalline thin film surfaces
Abstract The properties of artificially grown thin films are strongly affected by surface processes during growth. Coherent X-rays provide an approach to better understand such processes and fluctuations far from equilibrium. Here we report results for vacuum deposition of C60on a graphene-coated surface investigated with X-ray Photon Correlation Spectroscopy in surface-sensitive conditions. Step-flow is observed through measurement of the step-edge velocity in the late stages of growth after crystalline mounds have formed. We show that the step-edge velocity is coupled to the terrace length, and that there is a variation in the velocity from larger step spacing at the center of crystalline mounds to closely-spaced, more slowly propagating steps at their edges. The results extend theories of surface growth, since the behavior is consistent with surface evolution driven by processes that include surface diffusion, the motion of step-edges, and attachment at step edges with significant step-edge barriers.
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- Award ID(s):
- 1709380
- PAR ID:
- 10153405
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 10
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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