Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 39: Posters II (Topological insulators; Graphene; Spintronics and spin physics; Quantum information science)

HL 39.18: Poster

Tuesday, March 17, 2015, 14:00–20:00, Poster F

Graphene Ruthenium Complex Phototransistors — •Nicolai Walter — Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz Platz 1, D- 76021 Karlsruhe, Germany

Graphene exhibits interesting electronic, optical, and mechanical properties, e.g. ultrahigh charge carrier mobility, broad spectra transmission, and superior strain resistance. These features make graphene a promising material in a variety of fields, i.a. flexible electronics.

However, due to the negligible thickness (atomic monolayer) and therefore small optical absorption together with short recombination times an efficient photodetection is not possible with bare graphene. This issue can be addressed by using graphene heterostructures where other materials or structures make up for those shortcomings.

We investigate graphene heterostructure phototransistors, consisting of a layer of photoactive ruthenium complex molecules imbedded between two cvd graphene sheets. The molecules are functionalized by pyrene moieties which enable them to attach to the graphene surface by π-π-stacking. In order to apply a defined amount of molecules a nanoimprint technique is applied using PDMS stamps aiming towards a monolayer of molecules. After the fabrication of test samples, the interaction between the ruthenium complex molecules and the graphene is to be investigated by measuring the change in electronic properties with illumination. In order to further determine the type of photoresponse, a temperature dependence measurement shall be conducted within a cryostat down to 4 K.