Group seminar Experimental Physics I

8.11.2017 3:45 p.m., room: R-344
Johannes Knörzer (Max Planck Institut für Quantenoptik - Abt. Cirac)
Acoustic Traps and Lattices for Electrons in Semiconductors
29.11.2017 3:45 p.m., room: R-344
Michael Kaniber (Walter Schottky Institut, TU München)
Two-dimensional crystals and their coupling to plasmonic nanostructures

Over the past few years atomically-thin materials, such as graphene, boron nitride and the group-VI transition metal dichalcogenides (TMDC), have stimulated intense interdisciplinary research in condensed matter physics, chemistry and electrical engineering. Due to their unique mechanical, electrical and optoelectronic properties they have already been implemented into flexible electronic and photonic devices such as high-performance field effect transistors, optical sensors, photo-catalytic and photo-voltaic devices and, most recently, light emitting diodes and lasers spanning the visible, infrared and THz regions of the electromagnetic spectrum.

In this talk, I will present studies on atomically-thin layered semiconductors, such as MoS2 and MoSe2, their integration into functional devices [1] and the control of the second-order non-linear response from MoS2 bilayers by applying vertical dc-electric fields in SiO2/Al2O3-microcapacitors [2]. Furthermore, I will elaborate on the influence of He-ion irradiation in a Helium ion microscope (HIM) on the optical, vibrionic and valleytronic properties of MoS2 [3] and the potential application of HIM exposure in combination with TMDC heterostructures [4] for controlled defect engineering of single luminescence centres [5]. Moreover, I will demonstrate the capabilities of coupling the spontaneous emission of monolayer MoSe2 to the guided modes of nanoplasmonic slot-waveguides [6], where one observes clear evidence for waveguiding, paving the way towards a true nanoscale 2D crystal light source. Finally, if time permits, I will present first results on local photocurrent readout in such an electrically contacted nanoscale waveguide geometry [7].

Besides exploring and understanding fundamental light-matter-couplinga in nanoscopic materials, the general aim of our work is to combine low-dimensional semiconductor quantum materials with deterministically fabricated nanoscale optical hardware for on-chip integrated nanophotonic applications.

[1] J. Klein et al., Nano Lett. 16, 1554 (2016) [2] J. Klein et al. Nano Lett. 17, 392 (2017) [3] J. Klein et al. 2D Mater. 5, 011007 (2018) [4] J. Wierzbowski et al. Sci. Rep. 7, 12383 (2017) [5] J. Klein et al. in preparation (2017) [6] M. Blauth et al. 2D Mater. 4, 021011 (2017) [7] M. Blauth et al. unpublished results (2017)