Resonant electron tunneling through defects in GaAs tunnel diodes

Current-voltage characteristics of GaAs tunnel diodes are studied experimentally and theoretically. In theoretical calculations contributions of three different transport mechanisms are considered: direct tunneling processes, nonresonant multiphonon tunneling processes via defects, and resonant tunneling processes through defects. The comparison between theoretical results and experimental data reveals resonant tunneling as the dominant transport mechanism at voltages corresponding to the peak current. At higher voltages this mechanism is replaced by nonresonant tunneling, which is in its turn replaced by over-barrier transport at even larger voltages.