Spatially resolved Raman and cathodoluminescence probes in electronic materials: Basics and applications

Spatially resolved spectroscopy of both Raman and cathodoluminescence (CL) emissions represent a quite powerful characterization method in electronics. In this paper, the underlying physics that dictates the different characteristics of Raman and CL probes is revisited, deepened, and further interpreted in order to clarify how the different nature of those probes enables one bringing about different sets of complementary information. Furthermore, it is inquired into the causes for which data collected by the two different spectroscopic methods on the same material or device may, at a first glance, appear inconsistent to each other and, for some aspects, contradictory. Such differences and contradictions are then shown to disappear once the different nature of the two probes, especially with respect to their spatial response and morphology, is clarified and properly taken into account. Emphasis is finally placed on quantitatively describing the spatial response of Raman and CL probes and to apply such knowledge to elucidate the behavior of electronic materials. The two types of light emission are described according to a common formalism, which details their respective probe response functions in the three-dimensional space. Practical applications of Raman and CL spectroscopy to resolve highly graded fields of crystal orientation and elastic stress/strain in paradigm electronic materials are finally shown and compared. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim