Tantalum electrodeposition using a nanoporous anodic alumina template and a nanostructured gold/nickel-chromium glass-ceramic substrate

The electrodeposition and analysis of tantalum (Ta) nanotube arrays prepared from an ionic liquid, 1-butyl-1- methylpyrrolidinium bis(trifluoro-methylsulfonyl) imide (BMP[Tf2N]), using a porous anodic alumina (PAA) template are newly presented. Free-standing and spatially separated tantalum nanotube arrays were achieved after selective etching of the PAA. The high-rate electrodeposition of the nanotube arrays took only 10 s and achieved approximately 70 atomic percent Ta metal. Superficial X-ray photoelectron spectroscopy supplemented by an argon ion etching and depth profiling has proven the presence of tantalum metal. Additionally, tantalum electrodeposition was attempted using a sputter-deposited gold coating on a planar glass-ceramic substrate as the working electrode. Pores emerged within the sputter-deposited gold layer as a side result of the Ta electrodeposition step. Nano-to submicrometer large pores were created due to a foreign element penetration into the gold and etching effect of fluorides contained in the ionic liquid solution.