Communication—Electrodeposition of Indium Directly on Silicon

Direct electrodeposition of indium onto silicon paves the way for advances in microelectronics, photovoltaics, and optoelectronics. Indium is generally electrodeposited onto silicon utilizing a physically or thermally deposited metallic seed layer. Eliminating this layer poses benefits in microelectronics by reducing resistive interfaces and in vapor-liquid-solid conversion to III-V material by allowing direct contact to the single-crystal silicon substrate for epitaxial conversion. We investigated conditions to directly electrodeposit indium onto n-type Si(100). We show that a two-step galvanostatic plating at low temperatures can consistently produce smooth, continuous films of indium over large areas, in bump morphologies, and conformally into inverted pyramids.

Lead Electrodeposition from Triethylenetetramine Solution Containing Inhibitors

Lead can be efficiently electrodeposited from a number of common leaching agents such as mineral acids, carboxylic acids, and bases (hydroxides and ammonia). This paper reports the possibility to deposit lead from a triethylenetetramine solution, which is also a powerful extracting agent for lead sulfate. The high affinity of triethylenetetramine towards lead sulfate molecules makes it a promising candidate for lead recovery from various solid materials, including industrial secondary resources, sewages, and wastes. A popular methodology that can be found in the literature to recover metal from amine is based on purging a solution with carbon dioxide, resulting in lead carbonate precipitation. Here, the direct electrodeposition of lead from an amine solution was reported. The effects of the main process parameters, i.e., current density, temperature, and presence of additives, were examined to enhance the product quality. Bone glue, ethylene glycol, and polyvinylpyrolidone were used as perspective inhibitors of dendritic lead formation. It was shown that the addition of ethylene glycol can significantly reduce their formation as well as discoloration resulting from amine, producing lead metal with a 99.9% purity.

Spin Caloritronics in 3D Interconnected Nanowire Networks

Recently, interconnected nanowire networks have been found suitable as flexible macroscopic spin caloritronic devices. The 3D nanowire networks are fabricated by direct electrodeposition in track-etched polymer templates with crossed nano-channels. This technique allows the fabrication of crossed nanowires consisting of both homogeneous ferromagnetic metals and multilayer stack with successive layers of ferromagnetic and non-magnetic metals, with controlled morphology and material composition. The networks exhibit extremely high, magnetically modulated thermoelectric power factors. Moreover, large spin-dependent Seebeck coefficients were directly extracted from experimental measurements on multilayer nanowire networks. This work provides a simple and cost-effective way to fabricate large-scale flexible and shapeable thermoelectric devices exploiting the spin degree of freedom.