Chen H-H, Su S H, Chang S-L, Cheng B-Y, Chen S W, Chen H-Y, Lin M-F, Huang J C A
Department of Physics, National Cheng Kung University, Tainan, Taiwan 701, Taiwan.
Department of Electrophysics, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu, 30050, Taiwan.
Sci Rep. 2015 Jun 23;5:11623. doi: 10.1038/srep11623.
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 ~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.
为了在纳米尺度上改进基于石墨烯的多功能器件，必须阐明一种逐步且可控的制造工艺。在此，研究了室温下吸附在单层外延石墨烯（MEG）上的铋（Bi）吸附原子的一系列结构转变。Bi吸附原子经历从一维（1D）线性结构到二维（2D）三角形岛的结构转变，并且这种2D生长模式受波纹状衬底的影响。在Bi沉积时，会发生少量电荷转移，并且在隧道谱中可以观察到一个特征峰，反映了Bi吸附原子独特的电子结构。当退火至约500 K时，二维三角形Bi岛聚集成尺寸均匀的Bi纳米团簇（NCs）。因此展示了一种可控的制造方法。本文采用的方法为在MEG和相关系统上制造和表征周期性网络提供了思路，这对于实现基于石墨烯的电子、能源、传感器和自旋电子器件很有用。
