Pinned colloidal crystals: Controlling the self-assembly of thin colloidal crystals with lithographically patterned substrates

Alexandros Pertsinidis

Brown University, Providence, RI 02912 U.S.A.

Self-assembly of (sub)micron colloidal particles into ordered structures is a promising way of fabricating photonic band gap devices working in the near-infrared and visual spectrum. In our studies we focus on the effects of "pinning" on the ordering of 1-3 layers thick colloidal crystal confined between two substrates. The pinning potential is created by lithographically generating various patterns on one of the substrates. We have succeded in creating a) a monolayer "glassy" state by having a rough substrate as a random pinning potential, b) modulated (striped or hexagonal) 3 layer thick crystals on periodic hexagonal or square arrays of submicron posts.