Cantilever-free Techniques and Tools for Delivering Materials and Energy to Surfaces.

摘要

The thesis is divided into two parts. The first part, including chapter two through four, focuses on the fundamental understanding of polymeric materials transport and light energy delivery in cantilever-free scanning probe lithography (SBL). In Chapter two, I investigate the transport of block copolymer inks with varying viscosities, from an atomic force microscope (AFM) tip to a substrate. The size of the patterned block copolymer features has been determined to increase with dwell time and decrease with ink viscosity, which is explained by a mass transfer model.;In Chapter three, I explore the optical paths in apertureless pen array and find that by blocking the flat backing layer between pens, the optical interaction with the surface is dominated by the light at the tip of pens, allowing one to serially write sub-wavelength features. Furthermore, I find that the apertureless pen can be reversibly deformed to tune the illumination region from the submicrometer to micro-meter scale.;Chapter four introduces and evaluates the concept of using cantilever-free scanning probe arrays as structures that can modulate nanoscale ink flow and composition with light. By utilizing polymer pen arrays with an opaque gold layer surrounding the base of the transparent polymer pyramids, we show that inks with photopolymerizable or isomerizable constituents can be used in conjunction with light channelled through the pyramids to control ink viscosity or composition in a dynamic manner.;The second part of my thesis focuses on orientational control of metal nanoparticles and nanowires during capillary assembly. Chapter five and six describe the large-area alignment of multi-segmented nanowires and anisotropic gold nanoparticles in nanoscale trenches with control over their angular position facilitated by capillary forces. We elucidate the role of the geometry of the templates in the assembly of anisotropic nanoparticles consisting of different shapes and sizes. These insights allow us to design templates that immobilize individual triangular nanoprisms and concave nanocubes in a shape-selective manner. Furthermore, by studying the roles of interparticle forces in this method, we are able to construct face-to-face and edge-to-edge nanocube dimers and triangular nanoprism bowtie antennas.