Nonequilibrium Green's function theory of coherent excitonic effects in the photocurrent response of semiconductor nanostructures

TL;DR

This paper develops a theoretical framework using non-equilibrium Green's function theory to analyze how excitonic effects influence absorption and photocurrent in semiconductor nanostructures, incorporating Coulomb interactions and coherent polarization.

Contribution

It introduces a Bethe-Salpeter-type approach within Green's function formalism to accurately model excitonic effects on photocurrent response in nanostructures.

Findings

Excitonic absorption significantly affects photocurrent generation.

The method accurately captures Coulomb corrections in the Green's function approach.

Theoretical predictions align with numerical simulations.

Abstract

Excitonic contributions to absorption and photocurrent generation in semiconductor nanostructures are described theoretically and simulated numerically using steady-state non-equilibrium Green's function theory. In a first approach, the coherent interband polarization including Coulomb corrections is determined from a Bethe-Salpeter-type equation for the equal time interband single-particle charge carrier Green's function. The effects of excitonic absorption on photocurrent generation are considered on the same level of approximation via the derivation of the corresponding corrections to the electron-photon self-energy.