Fig. 2: Device structure characterization.

a Schematic diagram of the device structure. b SEM images of as-prepared SiNWA array, where the inset shows the corresponding plane view of the nanoarray. c Height profile of the PtSe2 film; the inset shows the corresponding AFM image. d, e TEM images of the PtSe2 film under different magnifications and cross-sectional TEM image of the PtSe2 film (inset of (d)). f High-resolution TEM image of PtSe2, where the distance between two layers is approximately 0.52 nm