Fig. 1: Direct visualization of diffusion processes for non-equilibrium vs. equilibrium environments. | npj 2D Materials and Applications

Fig. 1: Direct visualization of diffusion processes for non-equilibrium vs. equilibrium environments.

From: Direct visualization of out-of-equilibrium structural transformations in atomically thin chalcogenides

Fig. 1

a Schematic of the pathways for disintegration vs. decomposition of 2D layers in two discrete environments. b, e Scanning transmission electron microscopy (STEM) imaging of pristine bilayer MoS2, as transferred to the specific microfabricated heating chips with supporting SiNx membrane underneath for b fast heating (non-equilibrium) and e slow heating (equilibrium). c, f Post-heating images of MoS2 flakes for c fast heating showing nanoscale crystals with uniform intensity contrast and well-defined shapes and f slow heating showing disordered spherical structures with non-uniform thickness contrast, as imaged using annular dark field (ADF)-STEM. d Fast heating produces ordered nano-crystallites of MoS2 containing multiple phases while g slow heating causes decomposition of MoS2 leading to amorphous/disordered structures at the atomic scale. STEM images in d and g taken correspond to sub-regions in c and f, respectively (scale bars: b, c: 200 nm, d: 5 nm, e, f: 1 µm, g: 2 nm).

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