Transport properties of gated resonant tunneling diodes in the single electron regime

To investigate the transport properties of resonant tunneling diodes with dimensions in the submicron range, small area mesa diodes with surrounding Schottky gates have been processed. The gate turns out to provide excellent current control, which makes a resonant tunneling transistor operation mode feasible for our devices. In the single electron regime very distinct staircase-like features are observed in the current voltage characteristics. An accurate analysis of this staircase characteristic by means of magnetotransport measurements shows that tunneling through defect states can be ruled out as a reason for these current steps. Moreover, we show that the current steps are exclusively due to quantization effects of the gate potential. At high magnetic fields a saturation-like behavior of the step onset voltages occurs as a function of a magnetic field applied parallel to the direction of transport. This effect can be explained by boundary conditions for the electron number and the Fermi level in the electron supply layer next to the double barrier structure. (C) 1998 American Institute of Physics. [S0021-8979(98)01224-9].