Fig. 2: Fabrication and scanning transmission electron microscopy integrated differential phase contrast (STEM-iDPC) imaging of atomic defect configurations in free-standing monolayer WS2.
From: Unveiling sulfur vacancy pairs as bright and stable color centers in monolayer WS2
a–c Sequential STEM-iDPC image of a free-standing monolayer WS2. Defects introduced due to beam radiolysis are marked by white dashed lines. d High-magnification STEM-iDPC images of all defect species arising due to electron beam probing. In a left-to-right sequence, I: single sulfur vacancy (v1S); II: disulfide vacancy (v2S); III: paired-sulfur vacancy; IV: triplet sulfur vacancy; V, VI: two types of sulfur vacancy cluster; VII: sulfur vacancy chain. e Lattice measurements of d. f Corresponding atomic structure model of defect configurations in e. Sulfur vacancies are marked by dashed circles. g, h Simultaneous STEM-HAADF images of all defect configurations in free-standing WS2, along with corresponding lattice distortion measurements, showing agreement with iDPC images and experimental results for encapsulated monolayer WS2.
