Plasmon resonance properties of silver-patterned glass substrates fabricated by anodic alumina oxide templates

Ultra-thin anodic aluminum oxide membranes were prepared and served as deposition masks for fabrication of uniformly sized Ag nanodots with different aspect ratios on glass substrates. The surface plasmon resonance (SPR) properties of the supported Ag nanodots were investigated and compared with the predictions of the generalized Maxwell–Garnett theory. By modeling the nanodots as spheroids without adjusting their real geometrical parameters input to the calculation, the resulting theoretical SPR wavelengths are in good agreement with measured extinction peaks. The discrepancy between the theoretical and experimental plasmon resonance peak maxima is within 10 nm for the nanodots with an aspect ratio of less than 1.5. Although this wavelength discrepancy becomes large as the aspect ratio is increased, it is kept at approximately 35 nm for the nanodots with an aspect ratio of 2.44.