Increased peak current in AlAs/GaAs resonant tunneling structures with GaInAs emitter spacer

Abstract

Self-consistent simulation results are presented for the symmetric barrier AlAs/GaAs/AlAs resonant tunneling structures with a GaInAs emitter spacer well [Appl. Phys. Lett. 58, 1077 (1991)]. A simple model is used to handle the two-dimensional emitter accumulation electrons. These accumulation electrons below the emitter launching energy are treated as pseudo three-dimensional electrons, distributed continuously down to a certain minimum energy. With a proper choice of this bottom energy, a good agreement is achieved in the peak position between the simulation results and the experimental data. The best fit value of the bottom energy for the accumulated electrons was about 2/3ΔEc below the emitter conduction band edges for all diodes. Also, the simulation results could explain the systematic variation of the experimental peak current and voltage values as a function of the GaInAs spacer well depth. In order to provide a design guideline, the layer parameters were systematically varied and the simulation results on the peak current are presented. The peak current density is found to be most sensitive to the AlAs barrier thickness, especially to the emitter barrier thickness, and it is further increased by using an emitter spacer well. Based on our theoretical analyses, a 10-Å AlAs double barrier and 50-Å GaAs well with a 50-Å Ga0.9In0.1As emitter spacer well could produce a peak current density as high as 2200 kA/cm2.