Fabrication of a gated resonant tunneling diode with a laterally adjustable quantum dot cross-section

The authors report a novel technique used to place a rectifying contact at the well region of a unipolar Al/sub 0.3/Ga/sub 0.7/As/GaAs double barrier heterostructure. Application of a potential at this third terminal with respect to a common emitter depleted the vertical cross section, thereby decreasing the electrical size of the RTD (resonant tunneling diode). Transport measurements showed that at gate potentials less than 0.4 V, the gated RTD (GRTD) was effective in modulating current length through the RTD without appreciably affecting the resonant bias. It was shown that the tunneling cross section of the well region of a RTD can be electrically controlled, thereby suggesting the feasibility of in situ transition from a two-dimensional electron gas to a zero-dimensional quantum dot.>