The influence of a thin gold film on the optical spectral characteristics of a porous anodic aluminum-oxide membrane

We have experimentally studied how a thin mesostructured gold film, deposited onto one side of a porous anodic aluminum-oxide membrane, influences its optical spectral characteristics in a 200–900 nm wavelength range. It is established that the gold film only modifies the spectral characteristics of the composite membrane at light wavelengths above 500 nm. The presence of a thin gold film ensures the surface conductivity of membrane on a level of 3.4 $\times$ 10$^6$ $\Omega^{-1}$ m$^{-1}$, retains optical transparency within 10–20%, leads to the appearance of anomalous dispersion in the long-wavelength part of the transmission spectrum, and reduces the bandgap width from 5.61 eV (in anodic aluminum oxide) to 4.51 eV (in the composite). The obtained anodic aluminum-oxide membranes with thin gold films can be used as transparent conducting electrodes in optoelectronic devices with large light transmitter/receiver active areas.