Imaging Nanoscale Inhomogeneities and Edge Delamination in As-Grown MoS2 Using Tip-Enhanced Photoluminescence
| Main Authors: | Alvaro Rodriguez, Tim Verhagen, Martin Kalbac, Jana Vejpravova, Otakar Frank |
|---|---|
| Format: | info publication-preprint eJournal |
| Bahasa: | eng |
| Terbitan: |
, 2019
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/3578155 |
Daftar Isi:
- Methods for nanoscale material characterization are in ever-increasing demand, especially those that can provide a broader range of information at once. Near-field techniques based on combinations of scanning probe microscopy (SPM) and Raman or photoluminescence (PL) spectroscopy (tip-enhanced Raman spectroscopy [TERS] and/or tip-enhanced PL [TEPL]) are, thanks to their capabilities and fast development, strong candidates for becoming widespread across the scientific community as SPM and Raman microscopy did only a decade or two ago. The present work describes a gap-less TEPL study performed directly on as-grown MoS2 monolayer samples without any pretreatment or transfer, i.e. without the utilization of plasmonic substrate. Thanks to a mapping resolution as low as a few tens of nanometers, homogeneous layer interiors from defective edge fronts in the grown monolayers could be distinguished. With the aid of additional high-resolution SPM modes, like local surface potential and capacitance measurements, together with nanomechanical mapping, a combination of defects and a lack of substrate doping is suggested as being responsible for the observed PL behavior in the partially delaminated MoS2 layers. In contrast, mechanically exfoliated flakes show topography- and contamination-related heterogeneities in the whole flake area.