posted on 2023-11-03, 14:10authored byTheodore Hueckel, Diana J. Lewis, Alket Mertiri, David J. D. Carter, Robert J. Macfarlane
Colloidal crystallization provides
a means to synthesize hierarchical
nanostructures by design and to use these complex structures for nanodevice
fabrication. In particular, DNA provides a means to program interactions
between particles with high specificity, thereby enabling the formation
of particle superlattice crystallites with tailored unit cell geometries
and surface faceting. However, while DNA provides precise control
of particle–particle bonding interactions, it does not inherently
present a means of controlling higher-level structural features such
as the size, shape, position, or orientation of a colloidal crystallite.
While altering assembly parameters such as temperature or concentration
can enable limited control of crystallite size and geometry, integrating
colloidal assemblies into nanodevices requires better tools to manipulate
higher-order structuring and improved understanding of how these tools
control the fundamental kinetics and mechanisms of colloidal crystal
growth. In this work, photolithography is used to produce patterned
substrates that can manipulate the placement, size, dispersity, and
orientation of colloidal crystals. By adjusting aspects of the pattern,
such as feature size and separation, we reveal a diffusion-limited
mechanism governing crystal nucleation and growth. Leveraging this
insight, patterns are designed that can produce wafer-scale substrates
with arrays of nanoparticle superlattices of uniform size and shape.
These design principles therefore bridge a gap between a fundamental
understanding of nanoparticle assembly and the fabrication of nanostructures
compatible with functional devices.