Passivating etchants for metallic particles

摘要

The present invention provides a process for etching a corrosion layer, such as oxide or hydroxide, from and concomitantly forming a passivating layer on the surface of metallic nanoparticles. A reaction mixture is prepared by dispersing sodium hexafluoroacetylacetonate (Na(hfa)) and a metallic particle powder having oxide or hydroxide corrosion layers in hexane solvent. The mixture is allowed to react for a time sufficient to etch the oxide or hydroxide groups from the particulate surface and passivate the surfaces with (hfa). Hexane may be evaporated from the mixture and any excess Na(hfa) separated from the reaction mixture by sublimation or rinsing with a polar aprotic solvent. In an embodiment of the present invention, aluminum particles are first etched and passivated and then used to form ohmic contacts with p-type silicon. This etching/passivation improves the electrical properties of the contact.