Fig. 3: Microstructure of the BP films grown on silicon.
From: Epitaxial nucleation and lateral growth of high-crystalline black phosphorus films on silicon
a Cross-sectional TEM image of a BP film grown on silicon substrate and the corresponding element mapping of the P, Au, Sn, Si and O. b, c The SEM and close-up HRTEM image of the BP film in a. It uncovers that each BP film is regularly composed with few nanometer (~ 5–10 nm)-thick BP atomic layers as unit cells, with tiny gaps between each other. d Cross-sectional HRTEM image of a BP atomic layer derived from the as-grown BP film, displaying a clear layered structure with 0.5 nm spacing. e HRTEM image of the BP film, representing a defect-free atomic structure. The lattice parameters match well with those of bulk BP crystals, showing an orthorhombic symmetry in AB stacking mode. Insert displays the corresponding SAED pattern of the BP film, demonstrating its single-crystalline characteristic with zone axis along [100] direction.
