Semiconductor superlattices: artificial crystals with unique electronic and transport properties

Semiconductor superlattices are artificial crystals with a periodicity much larger than lattice constants of the constituent materials. Applying an electric field parallel to the superlattice axis, i.e., perpendicular to the layers, results in unique electronic and transport properties such as miniband transport and Wannier-Stark localization, which are the basis for the observation of Bloch oscillations. At larger field strengths, resonant tunneling between different mini- or subbands dominates the electronic transport properties. Miniband transport and resonant tunneling are highly nonlinear process resulting in interesting phenomena of self-organization of the field distribution