Paper SE+TF-TuA3
Surface Enhanced Raman Scattering from Silver Nanorod Array Substrates: Characteristics and Origin
Tuesday, November 10, 2009, 2:40 pm, Room C4
| Session: |
Glancing Angle Deposition II |
| Presenter: |
Y. Liu, University of Georgia |
| Authors: |
Y. Liu, University of Georgia
Z. Zhang, University of Georgia
R.D. Dluhy, University of Georgia
Y. Zhao, University of Georgia
|
| Correspondent: |
Click to Email |
Surface-enhanced Raman scattering (SERS) has been a powerful analytical tool in chemical and biosensing applications. Silver nanorod array fabricated by oblique angle deposition can give a very strong SERS enhancement (>108). The SERS enhancement depends strongly on the length of nanorods, the incident angle of excitation light, the polarization states of excitation light, and the reflectance from substrate. A modified Greenler’s model based on the reflection from a single Ag nanorod and the substrate as well as dipole radiation is proposed to explain these SERS characteristics. The theoretical calculation qualitatively agrees well with the experimental results. However, the location of the strongest SERS enhancement and the nature of such an enhancement are still unknown. To answer this question, we have designed another set of experiments, by taking the advantage of oblique angle deposition, to put Raman probe molecules on different locations of Ag nanorod array substrates and found that the apparent SERS enhancement factor is about 50 ~ 200 times from the surface of the nanorods than that from the Ag thin film surface under Ag nanorods array. These effects cannot be interpreted directly by the local electric field enhancement effect. By combining the local electric field effect calculated by three dimensional finite-difference time-domain method and the anisotropic optical absorbance of the SERS signal from the anisotropic Ag nanorod array, the numerical calculations are semi-quantitatively agree with the experimental results.
* This work is supported by National Science Foundation (NO. ECS-0701787) and US Army Research Laboratory (W911NF-07-2-0065).
References:
- Y. -J. Liu, J. -G. Fan, Y. -P. Zhao, S. Shanmukh, and R. A. Dluhy, Angle Dependent Surface Enhanced Raman Scattering Obtained from a Ag Nanorod Array Substrates, Appl. Phys. Lett. 89, 173134 (2006)
- J. D. Driskell, S. Shanmukh, Y. -J. Liu, S. B. Chaney, X. J. Tang, Y. -P. Zhao, and R. A. Dluhy, The Use of Aligned Silver Nanorod Arrays Prepared by Oblique Angle Deposition as Surface Enhanced Raman Scattering Substrates, J. Phys. Chem. C 112, 895 (2008)
- Y. -J. Liu, Y. -P. Zhao, Simple Model for Surface-enhanced Raman Scattering from Tilted Silver Nanorod Array Substrates, Phys. Rev. B 78, 075436 (2008)
- Y.-J. Liu, Z.-Y. Zhang, Q. Zhao, R. A. Dluhy, and Y.-P. Zhao, The Surface Enhanced Raman Scattering from Ag Nanorod Array Substrate: the Site Dependent enhancement and Layer Absorbance Effect, J. Phys. Chem. C, in press (2009)