Surface enhanced Raman spectroscopy and structural characterization of Ag/Cu chiral nano-flower sculptured thin films

Silver chiral nano-flower sculptured thin films with 3-, 4- and 5-fold symmetry were produced on copper substrates using oblique angle deposition method in conjunction with rotation of sample holder with different speeds at different sectors of each revolution corresponding to symmetry order of the acquired nano-flower. Atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) were employed to obtain morphologies and nano-structure of the films. Raman spectroscopy was performed on all samples that were subject to impregnation by 4,4′-bipyridine (C10H8N2) solution. A high degree of enhancement of the main bands at 1610, 1297, and 1009 cm−1 that can be assigned to the CC stretching mode, aromatic ring stretching ring and in-plane ring mode of 4,4′-bipyridine, is achieved.