SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 76: Plasmonics and Nanooptics III: Light-Matter Interaction and Spectroscopy II
O 76.1: Vortrag
Donnerstag, 30. März 2023, 10:30–10:45, WIL A317
Continuous-wave multiphoton-induced electron transfer in a biased tunnel junction driven by intense plasmonic fields — Chenfang Lin1, •Melanie Müller1,2, Faruk Krecinic1, Hiroko Yoshino1, Adnan Hammud1, Anlian Pan2, Martin Wolf1, and Takashi Kumagai3 — 1Fritz Haber Institute, Faradayweg 4-6, Berlin — 2Hunan University, Hunan 410082, China — 3Institute for Molecular Science, Okazaki 444-8585, Japan
Understanding photoinduced tunneling processes in the presence of intense plasmonic fields is of crucial importance for the design of plasmon-induced hot carrier technology and optical rectennas. However, in contrast to femtosecond laser excitation, the observation of multiphoton-induced electron transfer and the understanding of the role of hot carriers under intense continuous-wave (cw) illumination remains scarce. Here we exploit the strong spatial confinement of light inside the plasmonic gap of a scanning tunneling microscope (STM) to drive photocurrents with cw optical fields at local peak intensities up to 109 W/cm2 at low incident power. We find that the photoinduced tunneling current scales nonlinear (linear) with laser intensity at low (high) STM bias. To yield insight into the photoinduced tunneling process we analyze the photocurrent-voltage dependence for different laser wavelength and powers. We discuss two possible origins of the multiphoton-induced electron transfer, namely transport of photoexcited hot electrons and photon-assisted quantum tunneling into light-dressed states.