Mobility and energy-transport in degenerate hopping systems

TL;DR

This paper revises the drift diffusion model for degenerate hopping systems by adding an energy flux term, challenging the assumption that a constant quasi-Fermi level implies zero current, and offers broader insights into degenerate systems.

Contribution

It introduces a modified drift diffusion equation with an energy flux term, addressing inconsistencies in previous models of degenerate hopping systems.

Findings

Adding an energy flux term improves model accuracy

Constant quasi-Fermi level does not guarantee zero current

Method applicable to general degenerate systems

Abstract

Revisiting charge transport in degenerate hopping systems we present a modification to the drift diffusion equation where instead of employing the generalized Einstein relation we add an energy flux term thus solving several inconsistencies. This leads also to the conclusion that, contrary to common belief, a constant quasi-Fermi level does not necessarily ensure zero electrical current. While we revisit the drift diffusion process in the context of degenerate hopping systems, a considerable part of the argumentation put forward can be applied generally to degenerate systems.