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Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures
Published on: December 5, 2015
Local strain and tunneling current modulate excitonic luminescence in MoS2 monolayers
Yalan Ma1, Romana Alice Kalt1, Andreas Stemmer1
1Nanotechnology Group, ETH Zürich Säumerstrasse 4 Rüschlikon 8803 Switzerland mayala@student.ethz.ch astemmer@ethz.ch.
Abstract:
The excitonic luminescence of monolayer molybdenum disulfide (MoS2) on a gold substrate is studied by scanning tunneling microscopy (STM). STM-induced light emission (STM-LE) from MoS2 is assigned to the radiative decay of A and B excitons. The intensity ratio of A and B exciton emission is modulated by the tunneling current, since the A exciton emission intensity saturates at high tunneling currents. Moreover, the corrugated gold substrate introduces local strain to the monolayer MoS2, resulting in significant changes of electronic bandgap and valence band splitting. The modulation rate of strain on A exciton energy is estimated as -69 ± 5 meV/%. STM-LE provides a direct link between exciton energy and local strain in monolayer MoS2 on a length scale of 10 nm.
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