After noting the effect of defects upon the current-voltage characteristics of a GaAlAs barrier, a model was developed for electron transport (through semiconductor barriers); as induced by the presence of defects. According to this model, electrons tunneled from defect sites (where they were emitted by phonon-assisted tunnel emission or thermal emission) and into the barrier conduction band. A good fit with experimental data was found in the case of 106.6nm-thick GaAlAs barriers, which were embedded in GaAs, when the defect which was involved was the DX center that was associated with residual doping impurities.

J.C.Bourgoin, L.El Mir: Materials Science Forum, 1995, 196-201, 437-42