Fig. 1. Ledge-guided epitaxy of mono-oriented vertical 2D fin arrays for 2D multi-fin field-effect transistors (FETs).

a Schematic illustration for 2D multi-fin FETs potentially applied in advanced integrated circuits. b–d Schematic (b) and corresponding scanning electron microscopy (SEM) images of 2D Bi₂O₂Se fins with two perpendicular orientations on pristine LaAlO₃ (100) surface, including top view (c) and tilted view (d). e–g Schematic (e) and corresponding SEM images of ledge-guided epitaxial mono-oriented 2D Bi₂O₂Se fins on pre-treated LaAlO₃ (100) surface, including top view (f) and tilted view (g).