Popis: |
We have demonstrated stable surface-enhanced Raman spectroscopy (SERS) on arrays of Au nanorods aligned on a photocatalytic TiO2 layer. We used dynamic oblique deposition (DOD) in order to control the morphology of both the Au nanorods and the TiO2 layer so that both Au and TiO2 appear on the surface and play the roles of Raman enhancer and self-cleaner, respectively. TiO2 template layer was formed by depositing Ti2O3 onto heated glass substrate in an oxygen atmosphere so that it was ready as photocatalyst when the deposition was over, without post annealing in the air. A serial bideposition technique (SBD) at a deposition angle of 85° was used to control the morphology of TiO2 layer suitable for the growth of Au nanorods. Then, Au nanorods were arrayed by depositing Au with different deposition angles and thicknesses on the TiO2 layer. We investigated the photocatalysis and SERS properties of the samples and found that they show both good photocatalysis and strong signals of SERS although these properties varies depend on the deposition angle and thickness of Au layer. Most importantly, we found that the SERS signals measured on our samples have shown spatially-, temporally-stable characters which have not been observed before on the Ag or Au nanorods deposited on a SiO2 layer. This stability is interpreted in terms of the self-cleaning character due to the photocatalytic TiO2 template layer. |