Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 20: Graphen: Adsorption, intercalation and doping II (joint session O/TT)
O 20.2: Vortrag
Montag, 12. März 2018, 17:00–17:15, MA 043
Investigation of PbPc self-assembly on graphene: Atomic resolution and spectroscopy data — •Nhung Nguyen1,2, Ha Nguyen1, and Christoph Tegenkamp1 — 1TU Chemnitz — 2Duy Tan University, Vietnam
Shuttlecock-like lead-Phthalocyanine (PbPc) with its two equivalent stable up- and down states corresponding to ON/OFF switch is used for high density data storage of three- orders-magnitude capability higher than the present high density storage materials capability [1]. In addition, absorption of organic molecules on graphene surface due to the charge transfer mechanism between them is one of the promising methods to break the symmetries in graphene, localize the electronic states toward open a bandgap, which makes graphene useful as a nanoelectronics material [2]. Here the self-assembly of PbPc on one monolayer graphene/SiC surface is investigated by means of scanning tunneling microscopy and spectroscopy (STM/STS) in ultra-high vacuum. Due to the weak molecule-substrate interaction as well as the thermodynamic stability, shuttlecock PbPc molecules are only deposited with Pb atom pointing upward (face-up) into the first monolayer, but face-up or face-down states appear randomly on the second layer. The occupied and unoccupied orbitals of PbPc on graphene are distinguished intuitively. The influences of surface coverage, substrate temperature and substrate properties (buffer layer and quasi-free-standing graphene substrates) on self-assembly of PbPc will be discussed. [1] Phys Chem Chem Phys., 2015, 17,23651. [2] PhysRevB., 2009, 80, 033404.