Charge transport in organic nanoscopic systems: From organic semiconductors to 2d layered materials
Prof. Dr. Thomas Weitz (Physics of Nanosystems, Department of Physics, LMU München)
In this seminar I will review our recent results in 1) the field of organic electronics and 2) on charge transport in bilayer graphene. 1) Charge transport in small-molecule organic semiconductors is not only dominated by the u-overlap of adjacent molecules, but also by discontinuities in the crystal such as grain boundaries and the semiconductor / dielectric interface. For example, we have recently shown, that such grain boundaries significantly contribute to degradation of the thin film during extended operation (Mueller et al. PSS RRL 10 (2016) 339). 2) Bilayer graphene is a fascinating material, since it has a _nite density of states at the charge-neutrality point (i.e. where valence and conduction band meet). One of the consequences is, that exchange interaction in this system is large, even in the absence of a magnetic field. We have identified, that it opens a gap in the spectrum whose origin is still under discussion in the field (Weitz et al. Science, 330 (2010) 812).