Technological and Material Related Challenges for Large Area, High Aspect-Ratio, Near Teradot/Inch<SUP>2</SUP> Areal Density and Three-Dimensional Structuring of Polyaniline

Abstract

In this manuscript we report on a newly developed technology for the nanoscale processing of the conducting polyaniline (PANI) with an unprecedented areal patterning order and density control exceeding 0.25 teradot/inch2. High resolution electron beam lithography was used to generate ordered 2D and 3D templates. A novel type of resist and dose-modulated 3D-electron beam lithography (RDM-3D-EBL), extensively exploiting the intrinsic properties of resist-electron beam interaction is detailed. Surface initiated and template confined aniline polymerization, through catalytic activity of metallic platinum, was then exploited to provide a genuine method for controlled nanoscale processing of polyaniline, a prototypical conjugated polymer that definitively settled the concept of synthetic metals. Using nanoscale polymerization reactors, ultimate resolution patterning and processing control of single polyaniline nanostructures was feasible. Aspects of the nanoscale polyaniline growth mechanism are discussed and the highly controllable, sub-picogram scale fabrication is emphasized. Near teradot/inch2 pattern transfer technology, complex 3D structuring and physico-chemical functionalization of polyaniline can be subsequently harnessed to build a large variety of architectures with potential for emerging optoelectronic technologies. The method is scalable, can be applied on virtually any type of flexible or rigid substrates and provides a generic approach for nanopatterning surfaces with functional polymers. Technological and material related fabrication challenges are detailed and discussed.

Wavelength-scale lens microscopy via thermal reshaping of colloidal particles

“…However, they are limited either in processing speed or in resolution, precluding large-scale integration. Moreover, these schemes are mostly limited to surface structuring and, even if advances in bottomup self-assembly, likewise in top-down two-dimensional (2D) and 3D lithography techniques have shown great improvements [24][25][26][27][28][29][30][31][32], the realization of complex shape wavelength-scale lenses (for example with a base contact angle higher than 90 • as illustrated hereafter) and their precise positioning remain difficult tasks. Microlenses are of primary importance for integrated optical systems, and we show in the following that precise control of the lens morphology capacitates the fine-tuning of the optical characteristics.…”