Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 6: Two-dimensional Materials (Joint session of HL, DS and O, organized by HL)
HL 6.8: Vortrag
Montag, 7. März 2016, 12:00–12:15, H16
Investigating the Potential of TMD Monolayers as Photodetectors — •Maja Feierabend1, Gunnar Berghäuser2, and Ermin Malic2 — 1Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, TU Berlin, Hardenbergstr. 36, 10623 Berlin, Germany — 2Chalmers University of Technology, Department of Physics, SE-412 96 Gothenburg, Sweden
Transition metal dichalcogenides (TMDs) are promising materials for technological application in the area of optoelectronics. Due to the direct band gap and the extraordinarily strong Coulomb interaction, TMDs exhibit efficient light-matter coupling and tightly bound excitons [1]. As atomically thin materials, they are very sensitive to changes in the surrounding environment. This motivates a functionalisation approach, where external molecules are non-covalently attached to the material surface to control its optical properties.
Here, we theoretically investigate functionalized TMDs based on the density matrix formalism combined with tight-binding wave functions. Considering exemplary spiropyran molecules exhibiting a strong dipole moment, we predict pronounced spectral red-shifts and the appearance of an additional side-peak in the absorption spectrum of functionalized TMDs. Interestingly, we also observe a further peak splitting due to the intervalley coupling between the high-symmetry K/K’ points. The predicted pronounced changes in optical spectra of TMDs show their potential for technological application in photodetectors.
[1] G. Berghäuser and E. Malic, PRB 89, 125309 (2014)