A novel concept for electronic transport in nanoscale spaces formed by islandic multi-cored nanoparticles

Abstract

A nanocomposite system consists of nanoscale organic polymer spaces and islandic inorganic nano-particles. In this paper, a concept of quantum dots (QDs) is introduced to explain various dielectric properties of nanocomposites. Nano-particles are regarded as QDs rather than simple carrier traps. QDs exhibit negative permittivity. They also show Coulomb blockade effect, and inversely accept charge injection if they are subjected to high electric field beyond its barrier threshold. This concept can interpret key phenomena appearing in nanocomposites such as the reduction of permittivity, the threshold of space charge formation, the high field conduction and dielectric breakdown. Space charge formation and treeing phenomena are analyzed in more detail. A threshold for charge injection to QDs are obtained as the order of 100 kV/mm from the experimental data associated with both space charge and treeing.