Selective deposition of gold particles on dip-pen nanolithography patterns on silicon dioxide surfaces

We report a novel platform to perform selective deposition of gold nanoparticles on dip-pen nanolithographic patterns on SiO2 surfaces. An "inked" atomic force microscope (AFM) tip was adopted to deposit 2.2 mM organic N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTMS) molecules in nanopatterns through a water meniscus onto a SiO2 substrate under ambient conditions; the molecules act as linkers for the selective deposition of gold nanoparticles on the SiO2 surface. Conditions for dip-pen nanolithography of organic nanopatterns of AEAPTMS were investigated. In addition, gold nano-particles with negatively-charged citrate surfaces were deposited selectively on top of the organic patterns. X-ray photoelectron spectroscopy was then used to evaluate the presence of gold nanoparticles on the SiO2 surface. Lateral force microscopy was utilized to differentiate the surface between oxidized semiconductors and patterned areas with monolayer of AEAPTMS. Linewidths down to 60 nm have been successfully achieved by this method.