Tailoring coherent charge transport in graphene via nanoscale electronic structuring

Abstract

The wave-nature of charge carriers in solid state devices can be harnessed in coherent phenomena analogous to optics. While light wave manipulation is well established, recent efforts have focused on identifying suitable equivalents in electronics. However, the nanoscale dimension of the electronic wavelength in solids hinders the fabrication of complex gating architectures through standard nano-fabrication processes, limiting the range of realizable structures. Here, we present innovative coherent electronic devices in graphene achieved by deterministically nano-engineering the crystal’s structural properties to control the wave-like dynamics of charge carriers. This approach relies on the direct electron-beam nanopatterning of the graphene surface. This creates potential barriers with lateral resolution limited only by the beam focus, effectively overcoming the limitation of conventional metal electrodes. As first implementation, we fabricate multiple Fabry–Pérot cavities in graphene field-effect transistors by creating periodically alternating electron-irradiated (acting as partially reflecting mirrors) and pristine nano-stripes. The resonant modes manifest experimentally as sheet resistance oscillations, as also confirmed by Landauer–Büttiker simulations. These coherent phenomena persist up to 30 K for both carriers’ polarities, contrary to traditional electrostatically-created Fabry–Pérot interferometers. Our study establishes electron-irradiated graphene as an innovative platform for coherent electronics, with potential applications in sensing, optoelectronics, nano and quantum technologies.