Direct Visualization of Subnanometer Variations in the Excitonic Spectra of 2D/3D Semiconductor/Metal Heterostructures
Author(s)
Reidy, Kate; Majchrzak, Paulina Ewa; Haas, Benedikt; Thomsen, Joachim Dahl; Konečná, Andrea; Park, Eugene; Klein, Julian; Jones, Alfred J. H.; Volckaert, Klara; Biswas, Deepnarayan; Watson, Matthew D.; Cacho, Cephise; Narang, Prineha; Koch, Christoph T.; Ulstrup, Søren; Ross, Frances M.; Idrobo, Juan Carlos; ... Show more Show less
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The integration of metallic contacts with two-dimensional (2D) semiconductors is routinely required for the fabrication of nanoscale devices. However, nanometer-scale variations in the 2D/metal interface can drastically alter the local optoelectronic properties. Here, we map local excitonic changes of the 2D semiconductor MoS2 in contact with Au. We utilize a suspended and epitaxially grown 2D/metal platform that allows correlated electron energy-loss spectroscopy (EELS) and angle resolved photoelectron spectroscopy (nanoARPES) mapping. Spatial localization of MoS2 excitons uncovers an additional EELS peak related to the MoS2/Au interface. NanoARPES measurements indicate that Au–S hybridization decreases substantially with distance from the 2D/metal interface, suggesting that the observed EELS peak arises due to dielectric screening of the excitonic Coulomb interaction. Our results suggest that increasing the van der Waals distance could optimize excitonic spectra of mixed-dimensional 2D/3D interfaces and highlight opportunities for Coulomb engineering of exciton energies by the local dielectric environment or moiré engineering.
Date issued
2023-01-13Department
Massachusetts Institute of Technology. Department of Materials Science and EngineeringJournal
Nano Letters
Publisher
American Chemical Society
Citation
Reidy, Kate, Majchrzak, Paulina Ewa, Haas, Benedikt, Thomsen, Joachim Dahl, Konečná, Andrea et al. 2023. "Direct Visualization of Subnanometer Variations in the Excitonic Spectra of 2D/3D Semiconductor/Metal Heterostructures." Nano Letters, 23 (3).
Version: Author's final manuscript
ISSN
1530-6984
1530-6992
Keywords
Mechanical Engineering, Condensed Matter Physics, General Materials Science, General Chemistry, Bioengineering