Dresden 2020 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 47: Poster Session - 2D Materials: Electronic Structure, Excitations, etc.
O 47.12: Poster
Dienstag, 17. März 2020, 18:15–20:00, P2/EG
Strain tunable Photodetectors based on 2D materials: A case study of MoS2 monolayers — •Mohammad Bahmani1, Mahdi Ghorbani-Asl2, and Thomas Frauenheim1 — 1Bremen Center for Computational Materials Science, Department of Physics, Bremen University, Germany — 2Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Dresden, Germany
In monolayers of transition metal dichalcogenides (ML-TMDs), direct band-gap, weak screening of charge carriers, and a large surface-to-volume ratio facilitate the light-matter interactions in such materials, leading to noticeably high optical absorptions. Synthetic samples usually contain some fraction of intrinsic defects with significant effects on their electrical and optical properties. The localized defect levels have been observed to improve the photoresponsivity of MoS2 MLs by trapping the photoexcited charge carriers, thus increasing the photocurrent. Considering high resilience of ML-TMDs towards mechanical deformations, it was shown that biaxial strain improves the device properties of MoS2-based photodetectors. Recently, we showed the shift of the mid-gap levels of the defects inside MoS2 MLs as a function of various applied strains which could explain the observed improvements in photodetector devices. We study the properties of flexible photodetectors based on phase-engineered MoS2 MLs (1T-2H-1T) under strain. Using sisl tool, we employ a linear response regime to add the electron-photon interactions as a perturbation to the pristine Hamiltonian calculated by TranSIESTA/TBtrans.