MAGNETIC-FIELD DEPENDENCE OF THE ELECTRICAL CHARACTERISTICS OF A GATED RESONANT-TUNNELING DIODE

We have investigated the low-temperature I(V) characteristics of a gated submicrometer resonant-tunneling diode in the presence of a magnetic field applied perpendicular to the tunnel barriers. As the negative gate voltage is increased, additional maxima and minima are generated in forward bias with a typical voltage separation of 50 mV. This extra structure is only weakly dependent on magnetic field. In contrast the reverse bias I(V) closely resembles that of a large-area diode in all respects, including the appearance of additional peaks associated with optic-phonon-assisted tunneling between Landau levels. The structure in forward bias is similar to that observed by other groups in the I(V) of similar devices which was attributed to lateral quantum confinement. However, we show that simple models based on lateral confinement cannot account for our data.