70 research outputs found
Unravelling stacking order in epitaxial bilayer MX<sub>2</sub>using 4D-STEM with unsupervised learning
No full textFollowing an extensive investigation of various monolayer transition metal dichalcogenides (MX2), research interest has expanded to include multilayer systems. In bilayer MX2, the stacking order strongly impacts the local band structure as it dictates the local confinement and symmetry. Determination of stacking order in multilayer MX2 domains usually relies on prior knowledge of in-plane orientations of constituent layers. This is only feasible in case of growth resulting in well-defined triangular domains and not useful in-case of closed layers with hexagonal or irregularly shaped islands. Stacking order can be discerned in the reciprocal space by measuring changes in diffraction peak intensities. Advances in detector technology allow fast acquisition of high-quality four-dimensional datasets which can later be processed to extract useful information such as thickness, orientation, twist and strain. Here, we use 4D scanning transmission electron microscopy combined with multislice diffraction simulations to unravel stacking order in epitaxially grown bilayer MoS2. Machine learning based data segmentation is employed to obtain useful statistics on grain orientation of monolayer and stacking in bilayer MoS2.sponsorship: J.V. acknowledges funding from FLAG-ERA JTC2017 project 'Graph-Eye'. N.G. acknowledges funding from GOA project 'Solarpaint' of the University of Antwerp. This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 823717-ESTEEM3. 4D STEM data was acquired on a hybrid pixel detector funded with a Hercules fund 'Direct electron detector for soft matter TEM' from the Flemish Government. M. N. acknowledges funding from a Marie Curie Fellowship agreement No 838001. We thank Dr Jiongjiong Mo and Dr Benjamin Groven for developing the CVD-MoS2 growth on sapphire and providing the material used in this article. (FLAG-ERA JTC2017 project 'Graph-Eye', GOA project 'Solarpaint' of the University of Antwerp, European Union's Horizon 2020 research and innovation programme|823717-ESTEEM3, Hercules fund 'Direct electron detector for soft matter TEM' from the Flemish Government, Marie Curie Fellowship|838001, Marie Curie Actions (MSCA)|838001)status: Publishe
Unravelling Grain Orientation and Stacking Order in Bilayer MoS2 Using Electron Diffraction
No full text
High-Density Patterning of InGaZnO by CH<sub>4</sub>: a Comparative Study of RIE and Pulsed Plasma ALE
No full text
Importance of the substrate' s surface evolution during the MOVPE growth of 2D-transition metal dichalcogenides
No full text
- …
