Browsing by Author "Huang, J. C. A."

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Long-range interactions of bismuth growth on monolayer epitaxial graphene at room temperature
(2015-11-01)
Chen, H. -H.
;
Su, S. H.
;
Chang, S. -L.
;
Cheng, B. -Y.
;
Chong, C. -W.
Long-range electronic interaction between Bismuth (Bi) adatoms on graphene formed on a 4H-SiC (0001) substrate are clearly observed at room temperature (T = 300 K). Using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations, we have demonstrated that such oscillatory interaction results mainly from the mediation of graphene Dirac-like electrons and the effect of the corrugated surface of SiC substrate. These two factors cause the observed oscillatory interaction with characteristic distribution distances and linear arrangements of Bi adatoms. The present study sheds light on understanding and controlling the nucleation of adatoms and subsequent growth of nanostructures on graphene surface. (C) 2015 Elsevier Ltd. All rights reserved.
Tailoring low-dimensional structures of bismuth on monolayer epitaxial graphene
(2015-06-23)
Chen, H. -H.
;
Su, S. H.
;
Chang, S. -L.
;
Cheng, B. -Y.
;
Chen, S. W.
To improve graphene-based multifunctional devices at nanoscale, a stepwise and controllable fabrication procedure must be elucidated. Here, a series of structural transition of bismuth (Bi) adatoms, adsorbed on monolayer epitaxial graphene (MEG), is explored at room temperature. Bi adatoms undergo a structural transition from one-dimensional (1D) linear structures to two-dimensional (2D) triangular islands and such 2D growth mode is affected by the corrugated substrate. Upon Bi deposition, a little charge transfer occurs and a characteristic peak can be observed in the tunneling spectrum, reflecting the distinctive electronic structure of the Bi adatoms. When annealed to similar to 500 K, 2D triangular Bi islands aggregate into Bi nanoclusters (NCs) of uniform size. A well-controlled fabrication method is thus demonstrated. The approaches adopted herein provide perspectives for fabricating and characterizing periodic networks on MEG and related systems, which are useful in realizing graphene-based electronic, energy, sensor and spintronic devices.