The State of Electrodeposited Sn Nanopillars within Porous Anodic Alumina from in Situ X-ray Observations

Porous anodic alumina (PAA) can be used as a template for controlled electrodeposition and growth of nanostructures; it is also essential for long-lasting decorative coloring of aluminum. We have investigated the deposition of Sn nanopillars into PAA in situ, with grazing transmission small-angle X-ray scattering, X-ray fluorescence, and X-ray absorption near edge structure spectroscopy. An accumulation of Sn could be detected in the pores during the electrodeposition. From the X-ray absorption near edge structure spectroscopy measurements we could conclude that the deposited Sn was primarily in the metallic state. Ex situ scanning electron microscopy cross-section measurements show Sn nanopillars inside the PAA.