Raja, Archana and Selig, Malte and Berghauser, Gunnar and Yu, Jaeeun and Hill, Heather M. and Rigosi, Albert F. and Brus, Louis E. and Knorr, Andreas and Heinz, Tony F. and Malic, Ermin and Chernikov, Alexey (2018) Enhancement of Exciton-Phonon Scattering from Monolayer to Bilayer WS2. NANO LETTERS, 18 (10). pp. 6135-6143. ISSN 1530-6984, 1530-6992
Full text not available from this repository. (Request a copy)Abstract
Layered transition metal dichalcogenides exhibit the emergence of a direct bandgap at the monolayer limit along with pronounced excitonic effects. In these materials, interaction with phonons is the dominant mechanism that limits the exciton coherence lifetime. Exciton-phonon interaction also facilitates energy and momentum relaxation, and influences exciton diffusion under most experimental conditions. However, the fundamental changes in the exciton-phonon interaction are not well understood as the material undergoes the transition from a direct to an indirect bandgap semiconductor. Here, we address this question through optical spectroscopy and microscopic theory. In the experiment, we study room-temperature statistics of the exciton line width for a large number of mono- and bilayer WS2 samples. We observe a systematic increase in the room-temperature line width of the bilayer compared to the monolayer of 50 meV, corresponding to an additional scattering rate of similar to 0.1 fs(-1). We further address both phonon emission and absorption processes by examining the temperature dependence of the width of the exciton resonances. Using a theoretical approach based on many-body formalism, we are able to explain the experimental results and establish a microscopic framework for exciton-phonon interactions that can be applied to naturally occurring and artificially prepared multilayer structures.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | BAND-EDGE EXCITONS; OPTICAL-RESPONSE; BROADENING PARAMETERS; ELECTRONIC-STRUCTURE; SINGLE-LAYER; SEMICONDUCTOR; MOS2; RENORMALIZATION; LINEWIDTH; EVOLUTION; 2D materials; excitons; exciton-phonon interaction; scattering lifetime |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Chair Professor Huber > Group Rupert Huber |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 11 Dec 2019 09:21 |
| Last Modified: | 11 Dec 2019 09:21 |
| URI: | https://pred.uni-regensburg.de/id/eprint/13776 |
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