DPG Phi
Verhandlungen
Verhandlungen
DPG

Rostock 2019 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

MO: Fachverband Molekülphysik

MO 18: Posters 2: Time Resolved Spectroscopy

MO 18.9: Poster

Wednesday, March 13, 2019, 16:15–18:15, S Foyer LLM

Ultrafast Electronic Dynamics and Optical Excitation of Phonons in Hafnium Disulfide Crystals — •Simon Unger1, Franziska Fennel1, Chris Rehhagen1, Tim Völzer1, Kai Rossnagel2, and Stefan Lochbrunner11Institute for Physics, University of Rostock, Albert-Einstein-Str. 23-24, 18059 Rostock — 2Institute for Experimental and Applied Physics, University of Kiel, Leibnizstr. 19, 24118 Kiel

Transition metal dichalcogenides feature unique electronic and optical properties. Additionally, they consist of a layered structure, allowing the preparation of atomically thin crystals. Hafnium disulfide, as a representative of those materials, is considered to be a promising candidate for electronic and optoelectronic applications. To investigate the internal electronic processes and decay dynamics, static absorption and femtosecond pump-probe measurements were performed.

In the absorption spectrum, two bands are observed in the UV range. In the femtosecond pump-probe experiments, the sample is excited in the range of those bands and probed by a following white light pulse. The transient absorption signal shows a strong reduction in absorbance in the region of the original absorption, whereas at longer wavelengths a signal increase appears. This feature is an indication for a band gap renormalization induced by the population of excited charge carriers. The temporal evolution exhibits a fast sub-picosecond and a slower sub-nanosecond decay, caused by the relaxation and recombination of the charge carriers. Furthermore, the time traces show an oscillation pattern, which can be attributed to the excitation of acoustic phonons.

100% | Mobile Layout | Deutsche Version | Contact/Imprint/Privacy
DPG-Physik > DPG-Verhandlungen > 2019 > Rostock