Matrix-assisted dip-pen nanolithography

Abstract

Dip-pen nanolithography (DPN) is a direct -write lithographic technique which uses the atomic force microscope (AFM) tip as a pen and the substrate as a paper. The only difference comparing to the “writing” in our daily lives is that the dimensions of the “words” written by DPN is at the nano -scale and can only be read by the AFM, while the “dip pen” we use to write will generate words readable by our naked eyes. Thus DPN has been widely used in many different areas especially in the nanoscience and nanotechnology. However, fabrication of nanostructures using DPN is affected by many factors, which renders DPN unable to be a universal nanofabrication technique when nanomaterials or larger biomolecules are to be used as ink materials. In order to overcome this limitation, matrix-assisted dip-pen nanolithography (MA-DPN) whereby a polymer matrix is used to facilitate the diffusion of NMs from the AFM probe to the substrate surface is employed. By encapsulating the NMs in the polymer matrix, many different nanomaterials could be easily patterned onto various substrates. In this project, through the use of MA-DPN, fullerene nanoparticles (NPs) and gold (Au) NPs with varying sizes were fabricated into nanostructures on substrates using polyethylene oxide (PEO) as the polymer matrix.