High-resolution multidimensional space charge measurement using elastic wave methods -: art. no. 104106

In various fields of physics, materials can develop or exhibit a nonuniform space-charge distribution. During the last 20 years various approaches have been proposed for the direct measurement of these distributions involving optical, acoustical, or thermal processes. Most of them, however, lead only to one-dimensional distributions. In this paper we describe two approaches to obtain, in isotropic condensed matter, multidimensional space-charge distributions. They are based on the pressure-wave-propagation method and the electroacoustic method. In the case of the pressure-wave-propagation method, various independent measurements are performed with plane waves at different angles of incidence. A tomographiclike algorithm is then applied to retrieve the multidimensional space-charge distribution. In the case of the electroacoustic method, independent measurements are provided from a set of piezoelectric transducers at various positions. An echographiclike algorithm is then applied to retrieve the multidimensional space-charge distribution. A theoretical model is proposed, and preliminary experimental and simulated results showing the validity of these techniques are presented.