Using self-assembly for the fabrication of nano-scale electronic and photonic devices

Challenges facing the scaling of microelectronics to sub-50 nm dimensions and the demanding material and structural requirements of integrated photonic and microelectromechanical systems suggest that alternative fabrication technologies are needed to produce nano-scale devices. Inspired by complex, functional, self-assembled structures and systems found in Nature we suggest that self-assembly can be employed as an effective tool for nanofabrication. We define a self-assembling system as one in which the elements of the system interact in pre-defined ways to spontaneously generate a higher order structure. Self-assembly is a parallel fabrication process that, at the molecular level, can generate three-dimensional structures with sub-nanometer precision. Guiding the process of self-assembly by external forces and geometrical constraints can reconfigure a system dynamically on demand. We survey some of the recent applications of self-assembly for nanofabrication of electronic and photonic devices. Five self-assembling systems are discussed: 1) self-assembled molecular monolayers; 2) self-assembly in supramolecular chemistry; 3) self-assembly of nanocrystals and nanowires; 4) self-assembly of phase-separated block copolymers; 5) colloidal self-assembly. These techniques can generate features ranging in size from a few angstroms to a few microns. We conclude with a discussion of the limitations and challenges facing self-assembly and some potential directions along which the development of self-assembly as a nanofabrication technology may proceed.