Investigation of additives for electroless plating of nanowires

The goal of this work is to deposit nanoscale metal features on a nonconductive substrate in a specific and controlled manner in order to make nanoscale devices. To this end we studied the effects of several plating additives on electroless plating of nanoscale-thin layers in a model system, namely palladium metal on plain and chemically modified silicon oxide substrates. We selected and tested a series of candidate additives including sulfur- and sulfonate-containing molecules such as 3-mercapto-1-propanesulfonate (MPS) and propane disulfonate (PDS). Comparative growth rates, surface composition, morphology, and surface electrical conductivity on homogeneous surfaces were used as a proxy for determining the specificity and quality of deposits on a heterogeneous substrate. MPS and PDS showed the greatest effect on the electroless seeding and plating of palladium on the surface. This work shows that the use of particular additives under electroless plating conditions can lead to nanoscale-thin, selective, and conductive deposits of palladium metal.