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Schlagwörter:
Condensed Matter, Mesoscale and Nanoscale Physics, cond-mat.mes-hall, Condensed Matter, Materials Science, cond-mat.mtrl-sci, Physics, Optics, physics.optics
Zusammenfassung:
The ability to create high-quality lateral p-n junctions at nanometer length scales is essential for the next generation of two-dimensional (2D) electronic and plasmonic devices. Using a charge-transfer heterostructure consisting of graphene on α-RuCl3 , we conduct a proof-of-concept study demonstrating the existence of intrinsic nanoscale lateral p-n junctions in the vicinity of graphene nanobubbles. Our multi-pronged experimental approach incorporates scanning tunneling microscopy (STM) and spectroscopy (STS) and scattering-type scanning near-field optical microscopy (s-SNOM) in order to simultaneously probe both the electronic and optical responses of nanobubble p-n junctions. Our STM and STS results reveal that p-n junctions with a band offset of more than 0.6 eV can be achieved over lateral length scale of less than 3 nm, giving rise to a staggering effective in-plane field in excess of 108 V/m. Concurrent s-SNOM measurements confirm the utility of these nano-junctions in plasmonically-active media, and validate the use of a point-scatterer formalism for modeling surface plasmon polaritons (SPPs). Model ab initio density functional theory (DFT) calculations corroborate our experimental data and reveal a combination of sub-angstrom and few-angstrom decay processes dictating the dependence of charge transfer on layer separation. Our study provides experimental and conceptual foundations for the use of charge-transfer interfaces such as graphene/α-RuCl3 to generate p-n nano-junctions.
