TEM images and EDS spectrum of the triangular nanocrystals, f = 0.005 nm/s. (a) The high-resolution TEM image of the area marked in the inset, d = 3.0 nm. (b) EDS spectrum of the square area of the triangular Cu nanocrystal shown in the inset, d = 4.0 nm. The spectrum is presented with log scale on the y-axis.