Polymer templates realized through a combination of block
copolymer
lithography (BCL) and nanoimprint lithography (NIL) are used to direct
atomic layer deposition (ALD) to obtain high-quality ZnO nanopatterns.
These patterns present a uniform array of ZnO nanostructures with
sub-100 nm feature and spatial resolutions, exhibiting narrow distributions
in size and separation, and enhanced mechanical stability. The process
benefits from the high lateral resolutions determined by the copolymer
pattern, controlled growth rates, material quality and enhanced mechanical
stability from ALD and repeatability and throughput from NIL. The
protocol is generic and readily extendible to a range of other materials
that can be grown through ALD. By virtue of their high feature density
and material quality, the electrical characteristics of the arrays
incorporated within MOS capacitors display high hole-storage density
of 7.39 × 1018 cm–3, excellent retention
of ∼97% (for 1000 s of discharging), despite low tunneling
oxide thickness of 3 nm. These attributes favor potential application
of these ZnO arrays as charge-storage centers in nonvolatile flash
memory devices.