Selective self-alignment of Au nanoparticle-coated K₂SO₄microcrystals in micrometre gratings of V-grooves on a silicon substrate

Gold-nanoparticle-coated K2SO4 microcrystals were prepared by a recently reported self-assembly process and their organization onto micron-patterned silicon substrates was explored. Electron beam lithography, anisotropic chemical etching and high temperature thermal oxidation were used to fabricate oxidized or non-oxidized V-grooves on a silicon substrate and suspensions of gold-coated microcrystals were spin-coated over the surface. The nanoparticle-coated microcrystals were found to spontaneously deposit within the grooves and to form remarkably coherent structures made up of lines of microcrystals aligned relative to each other. Controls showed that this phenomenon was not observed with bare K2SO4 crystals suggesting a catalytic role for the gold nanoparticles in the organization process.