Eigenschaften von T- und Y-Schaltern aus Graphen

Graphene was expitaxially grown on 6H-SiC in a furnace with graphit chamber in an argon atmosphere at 1.5 bar. Dependence of the growth process on temperature and heating time were analyzed. The graphene quality, doping and thickness were analyzed with Raman spectroscopy. Infrared reflection spectroscopy allowed identifying surface plasmon related to graphene. Y-/T-Three Terminal Junctions (TTJ) were fabricated. The dependence of their rectifying behavior on the geometrical design was studied. Thereby a specific parameter was identified determining the behaviour of the TTJs. Furthermore, an explanation for the observation of diffuse behavior in TTJs with very narrow channels at a push-pull voltage close to zero is proposed. For the first time a switching, transistor like behavior is observed in TTJs made of graphene. The transconductance of these structures reaches values up to 440 S/m. The differential current gain is at maximum 560. An explanation for this behavior is attempted. Transmission conductance measurements of Titanium-Gold and Chrom-Gold contacts are conducted. The contact resistance is found to be 1600 m and 4400 m respectively.