EQUIVALENT NETWORK APPROACH FOR MULTISTEP DISCONTINUITIES IN ELECTRONWAVE-GUIDES

An analysis method is described for multistep discontinuities in elect ron waveguides composed of semiconductor heterostructures. The method is based on a rigorous mode-matching procedure that takes into account the effects of external finite potential and spatially varying effect ive mass. Stress is placed on network representations to establish phy sical pictures of the quantum effects and to yield insight; in additio n, a systematic microwave network approach is employed. The equivalent network representation is given for the waveguide modes propagating n ormally to the step discontinuity, and the mode-matching procedure is described for the boundary-value problem of the step discontinuity. Co mbining the above two procedures, the super-cascade matrix formulation is carried out, from which the reflection and transmission characteri stics of multistep discontinuities in electron waveguides can be estim ated. In order to show the validity and usefulness of this approach, e xamples are computed for constriction structures composed of three-lay ered electron waveguides.