We present the results of an experiment on 12.5 MeV Si4+ ion-irradiated InP
-based resonant tunneling diodes. Radiation damage suppresses the entire re
sonance in direct proportion to the ion fluence. The suppression is not cau
sed by a change in the tunneling barrier heights or widths, as previously t
hought; nor is it caused by radiation-induced increases in the leakage curr
ent. In fact, none of the internal parameters such as the Fermi energy and
the resonant energy of the quantum well are expected to be greatly altered
by the irradiation. We propose that radiation-induced disorder decreases th
e resonance current by scattering carriers out of the reduced-dimensional r
egion of k space in which tunneling is allowed. (C) 2000 American Institute
of Physics. [S0003-6951(00)01918-5].