Absorbance spectra of aligned Ag nanorod arrays prepared by oblique angle deposition

The s- and p-polarization absorbance spectra of Ag nanorod arrays with different heights prepared by oblique angle deposition are studied in detail. For short nanorods, both s- and p-polarization spectra, are dominated by a similar and single resonant peak. For long nanorods, a sharp UV peak dominates the s-polarization spectrum, while a broad vis–near infrared peak dominates the p-polarization spectrum. Three different absorbance peaks located at 293, 360, and 420–720nm, respectively, have been observed and evolve differently for s- and p-polarization absorbances with the nanorod height. The change of the absorbance as a function of the nanorod height is a reflection of the growth dynamics of the nanorod. The discrete dipole approximation was used to calculate the extinction spectra of Ag nanorod with 80-nm-diameter and different lengths, and the calculated results are qualitatively consistent with the experimental results.