QUASI-ONE-DIMENSIONAL TRANSPORT IN SEMICONDUCTOR MICROSTRUCTURES

We describe some of the physics peculiar to electron transport in quasi-one-dimensional systems in semiconductors, with particular reference to three systems in which it has been investigated: ultra-fine free-standing wires of doped GaAs, the split-gate high-electron-mobility transistor (with and without a back-gate to vary the carrier concentration), and vertical quantum pillars fabricated from multiple-barrier heterostructure material. They are all electron waveguide structures, characterized by less-than-or-equal-to 0.1 mum feature sizes in two of the three spatial dimensions, and they all exhibit phenomena quite different from those seen in macroscopic semiconductor structures. We try to identify the subset of this physics that may be exploitable, and comment on the more general relevance of this new physics to devices.