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HL: Fachverband Halbleiterphysik
HL 101: Graphene: Preparation and characterization II (O, jointly with HL, TT)
HL 101.10: Vortrag
Freitag, 15. März 2013, 12:45–13:00, H17
Morphological and Electronic Study of Moirè Patterns due to Dislocated Graphene on HOPG — •Dilek Yildiz1, Şener Şen2, Oğuz Gülseren2, and Oğuzhan Gürlü1 — 1Istanbul Technical University, Istanbul, Turkey — 2Bilkent University, Ankara, Turkey
Highly oriented pyrolytic graphite (HOPG) is widely used as a calibration sample for scanning tunneling microscopy (STM) studies. It is also used as a substrate in surface science because of its smooth surface. HOPG is composed of stacked two dimensional hexagonal lattices formed by carbon atoms, popularly named as graphene layers. Because of the weak van der Waals bonding between the graphene layers, the topmost layer may be shifted or rotated on HOPG. Due to the rotation of the top layer, super-periodic structures called as Moiré patterns form on HOPG. These formations were investigated in numerous studies; however, they are rediscovered in graphene research and their origin is still not understood. In this study we used different solvents to see their effects on HOPG samples and the formation of super-periodic structures on these surfaces. We investigate the morphological and electronic properties by using scanning tunneling microscopy and spectroscopy (STM and STS) under ambient conditions. We compared electronic properties of Moiré patterns due to their periodicities. In order to shed light onto the observed electronic structures we also performed ab initio calculations on these super periodic structures. (Supported by TUBITAK 109T687 and ITU-BAP 33263).