Electric-field effects on finite-length superlattices

In this paper, we study the Wannier-Stark ladder by carrying out numerical calculations on a multiple-quantum-well structure under an applied electric field. The variation in the Wannier-Stark-ladder energies and the degree of localization of the corresponding wave function are examined over a wide range of values of the applied electric field. Our results show that the Wannier-Stark ladder does exist for a finite, but periodic system that consists of a large number of quantum wells having a multiple-miniband structure.