Figure 2.

Wavelength tunability through control of multilayer GO film and through substrate selection. (A) SEM images of wrinkled GO films of thickness from 10 nm to 200 nm on the softer elastomer (modulus 5·10⁴ Pa) and (B) their Fourier transform spectra with the dominant spatial frequency shaded. (C) Thickness-dependent wavelengths on softer (black squares) and stiffer elastomer (modulus 6·10⁵ Pa; red circles) with linear regression slopes $\frac{\lambda }{h_f}$ shown. The scale bars in (A) represent 50 nm.