Figure 3. Tuning capabilities of Au nanoislands by using the repeated dewetting process.

(a) Extinction spectra of a single-step and repeated solid-state dewetting of thin Au film with (i) 5 nm, (ii) 7 nm, and (iii) 9 nm in thickness. Binary segments of Au nanoislands from the SEM images (left) and numerically calculated electric field intensity distributions at the plasmon resonance wavelength from the SEM images by using a three-dimensional finite difference time domain (3D-FDTD) method (right). (b) the effective diameters and (c) the effective gaps after a single-step and repeated solid-state dewetting processes. (d) the effective diameter and the gap depending on total Au film thickness. The black and blue lines indicate a single-step and repeated dewetting, respectively. The 3D-FDTD calculated and experimental (e) plasmon resonace wavelengths and (f) corresponding normalized extinctions of Au nanoislands after a single-step and double dewetting, i.e., repeated dewetting with the same thickness, depending on the effective diameter. The black and red lines indicate a single-step and repeated dewetting, respectively.