ABSTRACT
Semimetals are materials with an electronic structure somewhat in between that of metals and semiconductors. In a similar fashion to bandgap widening observed in semiconductors, nanopatterning semimetals results in a reduction of the valence band and conduction band overlap and subsequent bandgap opening, such that their electronic properties transition into those of a semiconductor. This chapter provides a theoretical overview of quantum-size effects observed in the electronic properties of semiconductors and semimetals which are particularly relevant to charge transport and briefly discusses how surface effects can further influence their electronic structure in significant ways. Semimetals patterned below certain critical dimensions-which can depend on several factors such as the bulk semimetal employed, number of confined directions, and surface properties-exhibit semiconducting properties. While the effects of quantum confinement are detrimental for silicon devices in highly integrated digital circuits, transistor designs based on semimetals can take advantage of these effects.
