Graphene Optoelectronics based on Antidot Superlattices

Graphene is well known for its outstanding electronic, thermal, and mechanical properties, and has recently gained tremendous interest as a nanomaterial for optoelectronic devices. We review our recent efforts on exfoliated graphene with a particular focus on the influence of graphene’s chiral edges on the electronic and optical properties. We first show that Raman spectroscopy can not only be used for layer metrology but also to monitor the composition of graphene’s zigzag/armchair edges. To elucidate the role of the localized edge state density, we fabricated dye sensitized antidot superlattices, i.e. nanopatterned graphene. The fluorescence from deposited dye molecules was found to quench strongly as a function of increasing antidot filling fraction, whereas it was enhanced in unpatterned but electrically back-gated samples. This contrasting behavior is strongly indicative of a built-in lateral electric field of up to 260 mV accounting for p-type doping as well as fluorescence quenching due to dissociation of electron-hole pairs from attached dye molecules. Our study provides new insights into the interplay of localized edge states in antidot superlattices and the resulting band bending, which are critical properties to enable novel applications of nanostructured graphene for light harvesting and photovoltaic devices.