Nanostructured Arrays Formed by Finely Focused Ion Beams

Nanoparticles can be formed in a variety of substrates by ion implantation and
thermal annealing. These particles range from a few to several hundred nanometers
in diameter and may be metals or semiconductors containing either single or multiple elements. Particles formed in this way are not uniform in size and are randomly
distributed throughout the implant region. The purpose of this work is to make
uniformly spaced lattices of colloidal particles of more uniform size by using a finely
focused ion beam to implant ions only into a microscopic region at each point of
a two-dimensional array. Simulations using a kinetic
lattice Monte Carlo code indicate that such implants should form localized distributions of colloids that may Ostwald ripen into a single large colloid at each
lattice site. Such a composite would exhibit greatly improved optical characteristics. Initial work is being done with 30 keV Ga and As in Si. Particle formation
as a function of implant and annealing conditions will be discussed