Adsorption Of The 1,3,5-triphenylbenzene Molecules And Growth Of The Graphene Nanoflakes On Cu(100) Surface

Graphene was firstly discovered by the group of physicists from England with the method of micromechanical cleavage in 2004.Graphene has many potential applications due to its outstanding electronic,magnetic,and thermal properties.However,for practical applications,precise control over the morphology and the size of graphene is of vital importance.Meanwhile,the bottom-up fabrication of graphene,namely carbonizing some special organic precursors on metal substrates(especially those highly active transition metal substrates)by thermal treatment,is the most ideal approach for precise control over the morphology and the sizeTherefore,in this paper,we report on the bottom-up fabrication of Graphene Nanoflakes(GNFs)on Cu(100)surface by molecular self-assembly using 1,3,5-triphenylbenzene(TPB)as precursor.Adsorption of TPB molecules and growth of the GNFs on Cu(100)surface was studied using Ultraviolet Photoelectron Spectroscopy(UPS),Angle Resolved Ultraviolet Photoelectron Spectroscopy(ARUPS)and Density Functional Theory(DFT)calculations.The three emission features d,e,and f/originating from the TPB molecules for 1.0 monolayer coverage locate at 3.095,7.326 and 9.349 eV below the Fermi level respectively.Work function decreases resulting from the formation of an interfacial dipole and charge(electron)rearrangement at TPB/Cu(100)interface,with the increasement of TPB deposition on Cu(100)substrate.Located at 1.100,3.529,6.984,8.465 and 9.606 eV below the Fermi level is the five emission characteristic peaks of g,hc i,j and k originating from the GNFs respectively.ARUPS and DFT calculations indicate that TPB molecules adopt lying-down configurations with their molecular plane nearly parallel to the Cu(100)substrate at monolayer stage.At the same time,lying-down configurations of GNFs growth on Cu(100)surface was discovered by ARUPS and DFT calculations.