A general method for controlled nanopatterning of oxide dots: a microphase separated block copolymer platform

Abstract

We demonstrate a facile, generic method for the fabrication of highly dense long range hexagonally ordered various inorganic oxide nanodots on different substrates by using a microphase separated polystyrene-b-poly(ethylene oxide) (PS-b-PEO) block copolymer (BCP) thin film as a structural template. The method does not require complex co-ordination chemistry (between metal precursors and the polymer) and instead involves the simple, solution based chemistry applicable to a wide range of systems. A highly ordered PS-b-PEO thin film with perpendicularly oriented PEO cylinders is fabricated by solvent annealing over wafer scale. PEO cylinders are activated by ethanol to create a functional chemical pattern for nanodot development via spin coating and block selective metal ion inclusion. Subsequent UV/ozone treatment forms an ordered arrangement of oxide nanodots and removes the polymer components. The phase purity, crystallinity and thermal stability of these materials coupled to the ease of production may make them useful in technological applications. This method is particularly useful because the feature sizes can be tuned by changing the concentration of the precursors without changing the molecular weight and concentration of the block copolymer.