Publications

Photoelectric polarization-sensitive broadband photoresponse from interface junction states in graphene

Kalugin, Nikolai G.; Jing, Lei; Morell, Eric S.; Dyer, Gregory C.; Wickey, Lee; Ovezmyradov, Mekan; Grine, Albert D.; Wanke, Michael W.; Shaner, Eric A.; Lau, Chun N.; Foa Torres, Luis E.F.; Fistul, Mikhail V.; Efetov, Konstantin B.

Graphene has established itself as a promising optoelectronic material. Many details of the photoresponse (PR) mechanisms in graphene in the THz-to-visible range have been revealed, however, new intricacies continue to emerge. Interface junctions, formed at the boundaries between parts of graphene with different number of layers or different stacking orders, and making connection between electrical contacts, provide another peculiar setup to establish PR. Here, we experimentally demonstrate an enhanced polarization sensitive photoelectric PR in graphene sheets containing interface junctions as compared to homogenous graphene sheets in the visible, infrared, and THz spectral regions. Our numerical simulations show that highly localized electronic states are created at the interface junctions, and these states exhibit a unique energy spectrum and enhanced probabilities for optical transitions. The interaction of electrons from interface junction states with electromagnetic fields generates a polarization-sensitive PR that is maximal for the polarization direction perpendicular to the junction interface.