Sample preparation for the stress-strain test and mechanical properties. (a) Schematic of sample preparation for conventional tensile test. (b) AFM and (c) TEM image of the film edge. (d) Comparison of tensile stress-strain curves for P1-P4 films. (e) Force-depth curves recorded by nanoindentation test. (f) Young’s modulus achieved by the conventional tensile test. (g) Elastic modulus and (h) hardness achieved by nanoindentation with the loading depth of 60, 120, and 180 nm.