Tuning of Energy Levels in a Superlattice

Abstract

AbstractThe gap between the minibands of a conventional superlattice (or between the subbands of a quantum well) can be controlled by introducing potential barriers in its wells. An appropriate choice of the position, the width d, and the height Vd of these barriers, achieved by standard methods, can reduce the energy minibands to the desired values. When these barriers are introduced at the center of the wells of the original structure, the position of the second miniband in energy space changes very little with d and/or Vd whereas that of the first miniband can change by one to two orders of magnitude. This leads to a tuning of the first miniband and of the energy gap between the first two minibands. Similar results are obtained for the case of wells in the barriers and for the tuning of impurity states in a superlattice. Possible applications include infrared photodetectors and tuning of the tunneling current.