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Thermodynamically Driven Tilt Grain Boundaries of Monolayer Crystals Using Catalytic Liquid Alloys.

Min-Yeong ChoiChang-Won ChoiDong-Yeong KimMoon Ho JoYong-Sung KimSi-Young ChoiCheol-Joo Kim
Published in: Nano letters (2023)
We report a method to precisely control the atomic defects at grain boundaries (GBs) of monolayer MoS 2 by vapor-liquid-solid (VLS) growth using sodium molybdate liquid alloys, which serve as growth catalysts to guide the formations of the thermodynamically most stable GB structure. The Mo-rich chemical environment of the alloys results in Mo-polar 5|7 defects with a yield exceeding 95%. The photoluminescence (PL) intensity of VLS-grown polycrystalline MoS 2 films markedly exceeds that of the films, exhibiting abundant S 5|7 defects, which are kinetically driven by vapor-solid-solid growths. Density functional theory calculations indicate that the enhanced PL intensity is due to the suppression of nonradiative recombination of charged excitons with donor-type defects of adsorbed Na elements on S 5|7 defects. Catalytic liquid alloys can aid in determining a type of atomic defect even in various polycrystalline 2D films, which accordingly provides a technical clue to engineer their properties.
Keyphrases
  • room temperature
  • density functional theory
  • ionic liquid
  • quantum dots
  • molecular dynamics
  • high intensity
  • gold nanoparticles
  • transition metal
  • dna repair