Depth Profiling in Organic Thin Films with Optical Guided Waves

Abstract

Many of the devices and schemes of importance in molecular electronics rely intimately on the precise manipulation of molecular entities with control of positioning and orientation on size scales ranging from molecular dimensions to many thousands of molecular diameters. Unfortunately the correct positioning of these assemblies must often be inferred from the macroscopic behavior of the device. It would be most beneficial if there were some way to obtain chemical structural information in situ. What we would like is a tool to tell us not only about the structure and orientations of individual layers of molecules, but also how these layers are related one to the other. Ideally the experiment would give us molecular information, it would be capable of both depth and lateral resolution, and it would be capable of being applied in situ. One such approach, developed in our laboratory makes use of the sample of interest as the active layer in an asymmetric slab dielectric optical waveguide [1].