Fig. 2: GPA of the fracture surfaces.
From: Flexible solar cells based on foldable silicon wafers with blunted edges
a,b, Morphology of the fracture surface of a wafer with sharp (a) and round (b) pyramids. The pink lines mark the locations at which the top surface of the fracture was protected and lifted out for TEM observations using an FIB. c,d, High-resolution STEM-HAADF images showing the atomic arrangement at a depth of dozens of atoms viewed along the [001] direction from the fracture surface of the wafer with sharp (c) and round (d) pyramids, in which a protective carbon layer was deposited on the fracture surface. The GPA regions are highlighted by dashed squares. e,f, Elastic lattice strain distribution in the x direction (e) and y direction (f) of the wafer with sharp pyramids. g,h, Elastic lattice strain distribution in the x direction (g) and y direction (h) of the wafer with round pyramids. White arrows mark the great dilatation strain. Positive and negative values represent lattice expansion and contraction, respectively. The x direction is parallel and the y direction is perpendicular to the fracture surfaces marked in a and b, respectively. Scale bars, 5 μm (a,b); 5 nm (c–h).
