Microstructural Characterization of Materials: An Assessment

Abstract

There is no doubt that the microstructural characterization of materials has played an important role for solving important problems in the fields of solid state physics, solid state chemistry, and materials research and technology during the past decades. Based on the close correlation between microstructure and properties of materials the characterization of materials in subnanometer regions (this means down to molecular and atomic dimensions) is one of the key tasks in these fields. In 1985 the Volkswagen-Stiftung responded to this situation with the establishment of a priority program entitled “Microcharacterization of Materials and Devices”. At that time electron microscopy (EM) had been the key method for this purpose, and the further development of this method, especially towards a better spatial resolution (for the imaging of both geometrical structures and chemical inhomogeneities), was regarded as the main task. Concerning the special field of the imaging of surfaces, the invention of scanning tunneling microscopy (STM) in the eighties yielded a powerful method for atomic imaging of surfaces, complementary to high-resolution transmission electron microscopy (HRTEM), which is mainly applied to image the interior of materials. Following the STM technique a great variety of scanning probe microscopies, especially atomic force microscopy (AFM), have been established. From the beginning of the nineties onwards not only the powerful methods of electron microscopy (having been applied successfully for many years) but also the rapidly expanding methods of scanning probe microscopies have been widely applied to the investigation of materials, and the priority program shifted its main goals from the development of characterization methods to the application of these methods in topical fields of materials research.