Negative resistance in a finite superlattice owing to quantum mechanical reflection

Abstract

Sasaki [Jpn. Inst. Electron. Commun. Eng. Tech. Rep. ED-84, 27 (1984)] has proposed a new type of superlattice, a modulation mass superlattice where the effective mass of electrons is changed periodically and the conduction-band edge is aligned so as to eliminate potential discontinuity. We investigate the quantum mechanical transmission of electrons for the case where a voltage is applied perpendicularly to the layers. We find that the modulation mass superlattice exhibits a new type of negative resistance owing to quantum mechanical reflection of electrons. The threshold voltage of negative resistance is much lower (around 10 mV than that (above 0.1 V) of compositional superlattice. The current density of the modulation mass superlattice is two orders of magnitude greater than that of a compositional superlattice. Such properties are very desirable for achieving a low-power ultrafast logic device.