B21-P-07Elucidating structure and thermal reaction of low-dimeansional Bi growth on monolayer epitaxial graphene

Abstract

The doping graphene with heavy metals can modify the number of carriers and spin-orbit coupling (SOC) can be exploited for novel electronic and spintronic applications. 1-2 This study elucidates the epitaxial growth structure and electronic properties of Bi on monolayer epitaxial graphene (MEG) surface by using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). Bi adatoms undergo a structural transition from linear structures at lower Bi coverage to two-dimensional (2D) triangular islands at thicker Bi coverage, which 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. After annealing to ∼500K, 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.