EFFECTS OF A LOW-DOPED SPACER LAYER IN THE EMITTER OF A RESONANT TUNNELING DIODE

An inflection is observed before the current peak in the current-voltage (I-V) curves of AlAs/GaAs superlattice resonant tunneling diodes with 500 Å 2×1016 cm-3 n-GaAs spacer layers between the n+ contact layers and the AlAs barriers. The inflection cannot be conclusively accounted for if the established model of end-to-end tunneling between the n+ contacts is applied. Evidence of an electron accumulation layer adjacent to the first upstream AlAs barrier suggests electron transport through the structure may be a two-step process and the I-V singularity a result thereof. The phenomenon is investigated by calculating conduction band profiles of the structures using a self-consistent solution to the time-independent Schrödinger and Poisson equations. © 1990.