Using self-assembly for the construction of nanoscale lateral-transport molecular electronic devices and microscale silicon-based networks

Self-assembly, the spontaneous organization of parts into ordered arrays and structures, is an omnipresent process in nature. Our group explores the use of self-assembly as an engineering concept to construct functional devices across the size scale. In this paper we present two examples of self-assembly. In the first example, we show how self-assembled monolayers of anthryl phosphonic acid can be used to form a nano-scale charge conduction channel. The molecular monolayer forms on a silicon dioxide surface and is placed between two metal electrodes. We have synthesized the molecules, verified the formation of the monolayer with X-ray photoemission spectroscopy and atomic force microscopy, and characterized the lateral charge carrier transport properties of the molecules. This molecular monolayer provides a facile way for integration of a nano-scale electronic device with conventional circuitry. In the second example, we demonstrate how microfabricated components can self-assemble into an electrical network. We have developed a microfabrication process for parallel production of 100 μm hexagonal silicon parts each carrying a portion of an electrical network. We functionalize the parts either with a low-melting point alloy or with a polymer and allow for their self-assembly into an ordered lattice at an air-water interface due to capillary forces.