Charge-quantization effects on current-voltage characteristics of AlGaAs/GaAs resonant tunneling diodes with spacer layers

An inflection has been observed in the current-voltage characteristics of several AlGaAs/GaAs resonant tunneling diodes with spacer layers. We provide evidence linking this inflection, as well as the negative differential resistance, to quasi-bound energy states localized in the charge accumulation well between the emitter spacer layer and the AlGaAs barrier. There are strong indications that this region acts as the injector of electrons through the quantum well region. We propose a model for the electron transport, and show that the singularities in the current are caused by the quantum well state crossing the accumulation layer quasi-bound states as the bias is ramped.