Binary information storage at zero bias in quantum-well diodes

Abstract

It is argued, based on the intrinsic time-dependent behavior of double-barrier structures, that a modification of a conventional quantum-well diode with special spacer-layer structure in the source and/or the drain region will lead to two stable current-voltage and charge state behaviors all the way down to zero bias. This viewpoint explains the salient features of a recent experimental observation on quantum-well diodes with n−-n+-n− spacer layers. We substantiate this with a simple theory of self-consistent charge buildup and bistability, and show that a limited supply or highly altered distribution of electrons from the emitter at high bias leads to fractional recharging of the quantum well and fractional current values, during the decreasing voltage sweep portion of a ‘‘closed-loop’’ voltage sweep. This is in contrast with previous theories based on numerical simulations which allow for more than two current states, by virtue of the use of time-independent analysis and/or the use of ‘‘open-multibranch’’ voltage sweep which do not correspond to the ‘‘closed-loop’’ voltage sweep in the actual experiments mentioned above. This two charge state phenomenon then is the basis for a feasible binary-information storage device at zero bias without dissipation.