hide
Free keywords:
-
Abstract:
The optical properties of inhomogeneously grown rough silver films have been analyzed on the basis of reflectance measurements. Data have been recorded within the wave number range 50 cm−1 < λ−1 <50 000 cm−1. The results are compared with compact and fairly smooth films, made from the same metal. Rough films reveal very low reflectance and high absorptivity values of nearly 1, at wave numbers ≳200 cm−1. The reflectance of these films is peaking at the bulk plasma resonance hvp of silver at 3.87 eV. Smooth compact films, in contrast, show a pronounced minimum at the same energy. Based on an effective medium approach and available literature data, the dielectric function (DF) and absorption coefficient have been calculated. For rough films, the real part of the DF remains positive within the whole spectral range, but is negative for compact films below hvp, in agreement with published data. The calculated DF of the inhomogeneously grown films fully resembles the experimental observations.
