Electronic transport in small strongly localized structures

We review some recent results on the low-temperature transport properties (T < 4K) of very small silicon metal-oxide field-effect transistors in the insulating regime of conduction. Our devices are lithographically patterned to have widths as small as 0.05 µm and lengths as short as 0.06 µm. These small transistors exhibit new and unexpected sample-specific fluctuation behavior in the gate voltage, temperature, and magnetic field dependence of the conductance. We discuss both resonant tunneling and Mott variable-range hopping, the two main transport mechanisms in these devices at low temperature.