THERMALLY ENHANCED CO-TUNNELING OF SINGLE ELECTRONS IN A SI QUANTUM-DOT AT 4.2 K

Transport properties of a Si quantum dot at 4.2 K have been studied. A quantum dot is realized in the inversion layer of a Si metal oxide-semiconductor field-effect-transistor (Si-MOSFET) with a dual-gate structure by introducing controllable tunnel barriers in the narrow channel. Periodic current oscillations due to the single-electron charging effect have been observed. With increasing tunnel barrier heights, Coulomb gaps appear in the I-V characteristics. Furthermore, leakage current in the Coulomb blockade regime varies linearly with bias voltage, which is quantitatively described in terms of the inelastic co-tunneling theory at finite temperatures.