MESOSCOPIC TRANSPORT IN SI METAL-OXIDE-SEMICONDUCTOR FIELD-EFFECT TRANSISTORS WITH A DUAL-GATE STRUCTURE

This article studies the mesoscopic transport of electrically controllable inversion layers of Si metal-oxide-semiconductor field-effect transistors that use a dual-gate structure. We have developed two kinds of devices: a quasi-one-dimensional device (1D-FET) and a Coulomb blockade device (CB-FET). In both devices, the field effect is used to change the channel structure by introducing potential barriers in the narrow inversion channel. The 1D-FET changes a long diffusive quantum wire into a short ballistic one. Strong oscillations in differential conductance, even negative differential conductance, have been observed at 4.2 K, indicating enhanced modulation of electron mobility by intersubband scattering suppression. The CB-FET, on the other hand, transforms a simple quantum wire into-a coupled quantum-dot array. A clear change in transport properties is observed with changes in the barrier height at low temperatures. The experimental results are consistent with the theory of one-dimensional subbands and the Coulomb blockade of single-electron tunneling.