SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 82: Graphene I: Adsorption, Intercalation and Doping
O 82.8: Vortrag
Donnerstag, 30. März 2023, 16:45–17:00, GER 37
Transport properties of intercalated epitaxial graphene — •Markus Gruschwitz, Zamin Mamiyev, Chitran Ghosal, Susanne Wolff, Thomas Seyller, and Christoph Tegenkamp — Institut für Physik, TU Chemnitz, Chemnitz, Germany
Large-scale growth and electronic manipulation of graphene are of great interest for nanoelectronics applications. The former is already realized by epitaxial growth and intercalation of buffer layers on SiC(0001). Electronic properties such as doping level and gap opening of the decoupled graphene layer strongly depend on the element and the structure of the interface. In this study we investigated Sn, Bi and In intercalated graphene by means of nanoscopic transport, supplemented by STM, LEED and PES. Depending on the film thickness and temperature, (1x1) phases can be formed with all three elements, accompanied by the formation of free-standing graphene. The fully intercalated phases show metallic conductivity behavior (σSn=0.63 mS/, σBi=0.74 mS/). The slightly lower conductivity of 10% compared to clean MLG is most likely due to interface scattering rather than different doping levels of the EG. Further heating allows the formation of √3-structures for all intercalants. Thereby, the conductivities drop by 2-3 orders of magnitude, accompanied by an increase of the anisotropy with respect to SiC step structure. This is indicative of inhomogeneous desorption especially around the step edges. The detailed analysis with the variable range hopping model yield localization lengths that correlate with the size of intercalated areas.