Imaging the crystal orientation of 2D transition metal dichalcogenides using polarization-resolved second-harmonic generation
Journal Title: Opto-Electronic Advances - Year 2019, Vol 2, Issue 11
Abstract
We use laser-scanning nonlinear imaging microscopy in atomically thin transition metal dichalcogenides (TMDs) to reveal information on the crystalline orientation distribution, within the 2D lattice. In particular, we perform polarization-resolved second-harmonic generation (PSHG) imaging in a stationary, raster-scanned chemical vapor deposition (CVD)-grown WS2 flake, in order to obtain with high precision a spatially resolved map of the orientation of its main crystallographic axis (armchair orientation). By fitting the experimental PSHG images of sub-micron resolution into a generalized nonlinear model, we are able to determine the armchair orientation for every pixel of the image of the 2D material, with further improved resolution. This pixel-wise mapping of the armchair orientation of 2D WS2 allows us to distinguish between different domains, reveal fine structure, and estimate the crystal orientation variability, which can be used as a unique crystal quality marker over large areas. The necessity and superiority of a polarization-resolved analysis over intensity-only measurements is experimentally demonstrated, while the advantages of PSHG over other techniques are analysed and discussed.
Authors and Affiliations
George Miltos Maragkakis, Sotiris Psilodimitrakopoulos, Leonidas Mouchliadis, Ioannis Paradisanos, Andreas Lemonis, George Kioseoglou, Emmanuel Stratakis*
Keywords
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- EP ID EP683119
- DOI 10.29026/oea.2019.190026
- Views 173
- Downloads 0
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