Tunnel junction I(V) characteristics: optimize and a new model for p–n homo-junctions

Abstract Despite the widespread adoption of tunnel junctions in high-efficiency devices such as multi-junction solar cells, tunnel field-effect transistors, and resonant tunneling diodes, accurately modeling their electrical behavior remains a significant challenge. This work builds upon the model proposed by Moulin et al and introduces a series of refinements aimed at enhancing the simulation of the current-voltage ( I(V) ) characteristics of Esaki tunnel junctions. Specifically, the calculation of the valley excess current is simplified through an improved treatment of its physical origin, while the influence of the electronic oscillation period is incorporated to better capture carrier dynamics. To further improve fitting accuracy in critical bias regions, such as the drift regime, a hybrid parameterization scheme and voltage-weighted loss function are introduced, combined with machine learning-based optimization. Additionally, the exponential excess tunneling current is incorporated into the model to account for high-bias conduction. A key innovation of the new model is the reinterpretation of the empirical parameter θ as a physically meaningful efficiency factor that quantifies the contribution of band-tail states to field-assisted tunneling. The proposed model provides a more comprehensive and physically grounded description of the I(V) behavior of tunnel junctions, demonstrating improved agreement with the experimental data. These advancements offer a valuable tool for the design, analysis, and optimization of tunneling devices in both electronic and photovoltaic applications.