Figure 7
Continuous wet etching of gold nanostructures in the undiluted etchant. a is SEM image of the sample before wet etching, which is obtained by evaporating 50 nm of gold onto the nanospheres of 175 nm in diameter at 70°, b shows the LSPR spectra of the sample after being wet etched for 1, 2, 3, 4, 5, 6, 8, 10, 15, 20, 30 min, c –j illustrate the shapes of the gold nanostructure before etching and after being etched 1, 2, 3, 4, 5, 6, and 8 min, respectively