Direct fabrication of uniform and high density Sub-10-nm etching mask using ferritin molecules on Si and GaAs surface for actual quantum-dot superlattice

Direct formation of a uniform, closely packed, and high-density two-dimensional array of ferritin molecules was successfully achieved on Si and GaAs substrates by modifying the surface using neutral beam oxidation, whereas the same protocol produced a low density and disorded array on thermal silicon oxide. The surfaces of neutral-beam-oxidized SiO₂ and GaAs and thermal silicon oxide were characterized, and the mechanism of ferritin array formation was investigated. The experimental results strongly suggested that the surface hydrophilicity realized by the neutral beam oxidation is essential for the formation of an ordered and high-density two-dimensional array of ferritin molecules.