Low Voltage Table-Top Electron Microscopy of Polymer and Organic Molecular Thin Films

摘要

There is intense current interest in the use of polymer and organic molecular materials for high technology devices including transistors, biosensors, and actuators (Wuerthner, 2001). In order for these materials to achieve their ultimate potential it is imperative to obtain detailed information about their microstructure, especially in the thin film forms central to technological applications. Our research group has been actively developing techniques for high-resolution electron optical examinations of polymers and organic materials, with particular emphasis on low dose high-resolution electron microscopy (HREM) (Martin, 2000). While this method of examining organic materials' structure has proven to be particularly powerful, current generations of electron microscopes suffer from several problems. They are quite expensive (typically $500k-$1500k), require considerable amounts of space, and are time-consuming and fairly difficult to operate. Furthermore, the high voltages normally used in conventional electron microscopes (200 ― 400 kV) provide little contrast when imaging thin films composed of low atomic number components.