Photocarrier extraction in GaAsSb/GaAsN type-II QW superlattice solar cells

TL;DR

This study uses advanced quantum transport calculations to analyze how design parameters affect carrier extraction efficiency in GaAsSb/GaAsN type-II superlattice solar cells, providing insights aligned with experimental observations.

Contribution

It introduces a detailed quantum transport modeling approach to understand carrier dynamics in type-II superlattice solar cells, linking theoretical predictions with experimental data.

Findings

Carrier extraction efficiency varies with superlattice configuration.

Transport regimes depend on layer thickness and electric field.

Model explains experimental performance trends.

Abstract

Photocarrier transport and extraction in GaAsSb/GaAsN type-II quantum well superlattices are investigated by means of inelastic quantum transport calculations based on the non-equilibrium Green's function formalism. Evaluation of the local density of states and of the spectral current flow enables the identification of different regimes for carrier localization, transport, and extraction as a function of configurational parameters. These include the number of periods, the thicknesses of the individual layers in one period, the built-in electric field, and the temperature of operation. The results for the carrier extraction efficiency are related to experimental data for different symmetric GaAsSb/GaAsN type-II quantum well superlattice solar cell devices and provide a qualitative explanation for the experimentally observed dependence of photovoltaic device performance on period thickness.