Figure 4: (a) Scanning-electron micrograph of gold nanochains ranging 1–9 particles in length. Scale bar is 300 nm. (b) SERS spectrum of benzenethiol on a nanochain comprised of 60 nm gold nanospheres. Measurements were taken with a 632.8 nm laser source polarized parallel to the nanochain axis. The red box in (a) denotes the heptamer from which this measurement was taken.