Space charge phenomenology in polymeric insulating materials

Topics related to space charge phenomenology, particularly the origin of space charge and its interaction with the host insulating polymer, have been widely discussed in recent years. Due to the development of reliable techniques for direct observation of space charge it is now possible to obtain, besides obvious indications on space charge and electric field magnitude and location, quantities that provide additional information on space charge accumulation and depletion rate, apparent mobility and trap depth distribution. Therefore, commonly debated topics such as the nature of charge carriers, the conduction mechanism, the charge dynamics at interfaces and the relation with nanostructure can be re-examined on the basis of space charge observation and this is, indeed, the purpose of this paper. Index Terms--Space charge, space charge limited conduction, charge carrier processes, polarization, nanotechnology, insulation, dielectric materials.