Templated Instabilities for Ordered Arrays of Nanomaterials

 Prof.  C. V. Thompson

Dept. of Materials Science and Engineering

M.I.T.

Cambridge, MA, USA

Abstract

We have investigated the templating of instabilities to produce highly ordered arrays of nanomaterials using topographic templates created through both conventional and achromatic interference lithography (IL and AIL).  Scanned IL and AIL can be used to create monoperiodic and diperiodic patterns over wafer-scale areas.   We have created instabilities in thin films deposited on diperiodic topographic patterns, and observed dewetting to form diperiodic arrays of monodisperse metal particles that can be used to catalyze nanotube or nanowire growth.  We have also used topographic patterning of the surfaces of Al films to template pore ordering during anodization.  This allows creation of pores that are perfectly ordered over large arrays, that also have controlled ordering symmetry  and independently controlled pore spacings and pore diameters.  Long-range ordered arrays of high-aspect-ratio small-diameter pores have been used to both create catalysts arrays for growth of nanotubes and to provide a scaffold for nanotube growth.  Instabilities lead to self-assembly of structures with a range of stable characteristic length scales.  In the experiments described above we demonstrate a general approach to templating of instabilities to select specific characteristic spacings from the range of possible length scales, to produce highly ordered periodic structures with chosen periodicities and sizes.