Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 33: 2D Materials and Heterostructures: Optoelectronics

HL 33.1: Talk

Wednesday, March 20, 2024, 15:00–15:15, EW 201

Surface acoustic wave-controlled photocurrent in few-layer WSe2 — •Benjamin Mayer, Clemens Strobl, Matthias Weiß, Hubert Krenner, Ursula Wurstbauer, and Emeline Nysten — Institute of Physics, University of Münster, Germany

The unique combination of piezo-electric surface acoustic waves (SAWs), high-resolution optical spectroscopy and electrical transport provides a versatile testbed to sense and manipulate the optical properties and carrier transport processes in novel nanoscale materials and opens pathways to novel acousto-optoelectronic devices [1]. Here, we present the fabrication and validation of a hybrid platform comprising strong SAW-devices on piezoelectric LiNbO3 and mechanically exfoliated transition metal dichalcogenide (TMDC) 2D materials. In our experiments, we employ the SAWs dynamic electric field with a frequency of 150-250MHz to induce a SAW power dependent Acousto-Electric Current (AEC) in few-layer WSe2 placed on top of two gold electrodes. The SAW directional dependence of this fundamental effect enables a detailed investigation of the Au-TMDC interface. Furthermore, the TMDC can be photodoped via excitation with a green laser (532nm) to deeply study the underlying charge carrier dynamics. In the low SAW-Power regime photogating leads to an enhanced AEC by two orders of magnitude, whereas bipolar charge carrier transport sets in for higher SAW powers. [1] J. Phys. D:Appl. Phys. 52(35):353001 (2019)

Keywords: surface acoustic waves; acousto-electric effect