Direct visualization of subnanometer variations in the excitonic spectra of 2D/3D semiconductor/metal heterostructures

DOI: 10.1021/acs.nanolett.2c04749

Authors: Kate Reidy (Massachusetts Institute of Technology) , Paulina Ewa Majchrzak (Aarhus University) , Benedikt Haas (Humboldt-Universität zu Berlin) , Joachim Dahl Thomsen (Massachusetts Institute of Technology) , Andrea Konečná (Brno University of Technology) , Eugene Park (Massachusetts Institute of Technology) , Julian Klein (Massachusetts Institute of Technology) , Alfred J. H. Jones (Aarhus University) , Klara Volckaert (Aarhus University) , Deepnarayan Biswas (Aarhus University) , Matthew D. Watson (Diamond Light Source) , Cephise Cacho (Diamond Light Source) , Prineha Narang (UCLA) , Christoph T. Koch (Humboldt-Universität zu Berlin) , Soeren Ulstrup (Aarhus University) , Frances M. Ross (Massachusetts Institute of Technology) , Juan Carlos Idrobo (University of Washington)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nano Letters

State: Published (Approved)
Published: January 2023
Diamond Proposal Number(s): 25368 , 29607

Abstract: 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.

Journal Keywords: excitons; electron energy-loss spectroscopy (EELS); angle resolved photoemission spectroscopy (nanoARPES); dielectric screening

Diamond Keywords: Semiconductors

Subject Areas: Materials, Physics


Instruments: I05-ARPES

Added On: 16/01/2023 08:45

Discipline Tags:

Physics Materials Science Nanoscience/Nanotechnology

Technical Tags:

Spectroscopy Angle Resolved Photoemission Spectroscopy (ARPES) Nano ARPES