TUNNELING AND NONRESONANT NEGATIVE DIFFERENTIAL RESISTANCE IN NARROW-WELL INTERBAND-TUNNELING DEVICES

We predict the observation of negative differential resistance (NDR) in, interband tunneling devices (ITD's) of well width smaller than 100 angstrom. This strong NDR results from the nature of tunneling in ITD's, and is not related to resonant tunneling. It is inherent to the ITD structure and should be experimentally observed in any symmetric ITD (including polytype structures). The mechanism is given in terms of simple physical arguments. Rigorous calculations of the current voltage characteristics of narrow-well ITD's are then made in the framework of the effective-mass approximation.