Sub-Micron Vertical AlGaAs/GaAs Resonant Tunneling Single Electron Transistor

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Abstract
We explore vertical transport phenomena in sub-micron asymmetric AlGaAs/GaAs double barrier structures (DBS's) by applying a bias to a special Schottky side gate which allows the effective area of the conducting channel to be adjusted or “tuned”. The AlGaAs barriers are selectively doped to generate excess electrons in the GaAs well, and thus single electron transistor (SET) operation is possible because the number of electrons in the quantum dot can be varied one-by-one with the side gate. Gate modulation of the drain current flowing through the conducting channel is found to be strong, and this allows us to study Coulomb blockade, electron-electron interactions and lateral confinement effects. Observation of a broad (≈18 mV) current plateau at low bias when the quantum dot is occupied by a single electron, suggests that this technology is very promising for the realization of SET operation at temperatures well above 4.2 K.