Dresden 2020 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 23: Ultra-fast phenomena
HL 23.5: Talk
Tuesday, March 17, 2020, 10:30–10:45, POT 112
Structural Dynamics in Nanostructured Systems Probed by Ultrafast Transmission Electron Microscopy — •Nora Bach1, Armin Feist2, Marcel Möller2, Claus Ropers2, and Sascha Schäfer1 — 1Institute for Physics, University of Oldenburg, Germany — 24th Physical Institute - Solids and Nanostructures, University of Göttingen, Germany
A successful approach to investigate ultrafast nanoscale structural dynamics and to disentangle different excitation mechanisms in spatially inhomogeneous systems is based on local diffractive probing with nano-focussed femtosecond electron pulses in an ultrafast transmission electron microscope (UTEM).
Employing the advanced electron pulse properties of the Göttingen UTEM [1,2] in ultrafast convergent electron beam diffraction (U-CBED) mode [3], we study local dynamics in a multi-component model system consisting of a metal-/semiconductor hybrid structure. Ultrashort optical excitation of platinum stripes on a silicon membrane results in the generation of hot electrons and their subsequent coupling with the underlying silicon substrate. Pronounced lattice distortions are quantitatively tracked by U-CBED, and experimental results are compared to finite element simulations in order to provide deeper insights into local couplings and the efficiency of electronic and phononic transport channels across interfaces.
[1] A. Feist, N. Bach, et al., Ultramicroscopy 176, 63 (2017).
[2] N. Bach et al., Structural Dynamics 6, 014301 (2019).
[3] A. Feist et al., Structural Dynamics 5, 014302 (2018).