Microscopic non-equilibrium theory of quantum well solar cells

TL;DR

This paper develops a detailed microscopic non-equilibrium Green's function model for quantum well solar cells, capturing carrier dynamics, scattering, and photogeneration to better understand their photovoltaic behavior.

Contribution

It introduces a comprehensive quantum kinetic framework for bipolar quantum well structures, integrating electron-hole interactions, scattering, and photogeneration at a microscopic level.

Findings

Analysis of local density of states in quantum wells

Spectral response and current-voltage characteristics

Impact of scattering mechanisms on device performance

Abstract

We present a microscopic theory of bipolar quantum well structures in the photovoltaic regime, based on the non-equilibrium Green's function formalism for a multi band tight binding Hamiltonian. The quantum kinetic equations for the single particle Green's functions of electrons and holes are self-consistently coupled to Poisson's equation, including inter-carrier scattering on the Hartree level. Relaxation and broadening mechanisms are considered by the inclusion of acoustic and optical electron-phonon interaction in a self consistent Born approximation of the scattering self energies. Photogeneration of carriers is described on the same level in terms of a self energy derived from the standard dipole approximation of the electron-photon interaction. Results from a simple two band model are shown for the local density of states, spectral response, current spectrum, and current-voltage characteristics for generic single quantum well systems.