(under subclass 184) Subject matter wherein the active region contains a number of layers forming plural heterojunctions and the carrier (i.e., electron or hole) affinities of each layer incrementally increase or decrease progressively across the active region thickness, so that the energy level diagram of the active region, when under electrical bias, resembles a staircase.
(1) Note. Staircase effect devices may also be provided with a graded composition, i.e., wherein the chemical composition of the semiconductor forming the heterojunction varies in a direction either perpendicular or parallel to the junction.
(2) Note. See illustration, below, for an example of a staircase bandgap. [figure]
