Block copolymer-assisted nanopatterning of porous lead titanate thin films for advanced electronics

Abstract

Chemical self assembly of functional ferroelectric PbTiO3 using amphiphilic block copolymers is used to prepare low cost nanopatterned porous thin films with nanostructure control down to ∼22 nm of lateral size. The approach developed in this work is highly effective in patterning PbTiO3 and avoids costly high resolution lithography techniques and harmful etching processes. Nanopatterned films presenting a honeycomb like arrangement of pores with diameters between 80 and 140 nm are obtained. The ordering and thickness of the films are discussed as a function of the precursors concentration and withdrawal rate used for films dip coating. The nanopatterned porous films with thickness of 22 nm exhibit tetragonal perovskite crystallographic phase and ferroelectric response at the nanoscale. These films display vertical open porosity from the film surface to the substrate, leading to nearly 50% of the substrate surface being accessible to further functionalization toward low cost, sustainable, multifunctional composites for the microelectronics industry.