Research Paper: GaAsSb/GaAsN Superlattices for Thin High-Efficiency Solar Cells
Summary
This study evaluates 1 eV GaAsSb/GaAsN superlattice absorbers and shows that mobility, lifetime, and unintentional doping limit carrier extraction. Using Setfos modelling and new MBE-grown samples, the authors identify 250–500 nm as the optimal absorber thickness, boosting efficiency by up to 4× compared to thicker devices. Setfos provided calibrated optical/electrical simulations that matched JV and EQE experiments and guided device optimization.
Publication details
Simulation, optimization, and experimental validation of 1 eV GaAsSb/GaAsN superlattice solar cells.
Authors: Schwarz, M., Gallego Carro, A., Gonzalo, A., Braza, V., Gonzalez, D., Hierro, A., Aeberhard, U., & Ulloa, J. M.
Journal: Solar Energy Materials & Solar Cells (2026)
DOI: https://doi.org/10.1016/j.solmat.2025.114057
PDF: Available on publisher website (open access)
Fluxim tools used
Setfos — optical modelling, drift–diffusion simulation, SRH extraction, EQE modelling, absorber-thickness optimization.
Why this research matters
Identifies the true mobility/lifetime limits of dilute-nitride superlattices.
Demonstrates validated modelling workflows for III–V metamaterials.
Shows how thin absorbers enable high PCE in next-generation multi-junction stacks.
Keywords
GaAsSb/GaAsN; superlattice; 1 eV absorber; III–V solar cells; type-II alignment; carrier mobility; SRH lifetime; unintentional doping; drift–diffusion; Setfos; EQE; JV; absorber-thickness optimization; multi-junction; thin-film PV.
FAQs
Which Fluxim tool was used and why?
Setfos was used for optical and drift-diffusion simulations, SRH-lifetime extraction, mobility fitting, EQE modelling, internal-field mapping, and absorber-thickness optimization. Its calibrated model accurately predicted experimental device performance.
Why is the optimal absorber thickness 250–500 nm
Thinner devices collect carriers efficiently despite lower absorption. Thicker devices generate more carriers but lose them through recombination because mobility, SRH lifetime, and UID flatten the internal field.