Extended defects in semiconductors could trap charge and lead to changes in carrier concentration and mobility. Here the trapping effects of pores, micro-cracks, and dislocations in GaN and SiC were considered, as analyzed by deep-level transient spectroscopy, transmission electron microscopy and scanning surface potential microscopy. The defect structures were modeled as spheres, plates, and cylinders for pores, cracks, and dislocations, respectively, and their potentials were directly compared with those measured by holographic transmission electron microscopy. The dynamics of the capture and emission processes were investigated by deep level transient spectroscopy, although the standard deep level transient spectroscopy analysis framework was not applicable here and must be replaced by a more general formalism. As an example, 40nm-diameter nanopores in SiC could each hold more than 100 electrons, and they exhibited anomalous capture and emission properties.

Giant Traps Associated with Extended Defects in GaN and SiC. D.C.Look, Z.Q.Fang, A.Krtschil, A.Krost: Physica Status Solidi C, 2005, 2[3], 1039-46