Flexible GaAs solar cells via graphene-assisted epitaxial lift-off

The principal aim of this research is to develop flexible solar cells for in-situ solar power generation and energy storage applications. The goal is to demonstrate feasibility by fabricating proof-of-concept devices in order to develop a single-junction GaAs solar cell epitaxially grown by metal-organic chemical vapour deposition (MOCVD) and lifted off from the substrate. GaAs-based thin films are epitaxially grown on top of MOCVD-grown graphene coated AlGaAs/GaAs substrate with a sacrificial buffer layer, which enables epitaxial lift-off of the solar cell. Besides, the structural properties of the GaAs films, graphene and GaAs-based substrate were characterized through SEM, AFM and Raman spectroscopy. Moreover, the optical properties of the GaAs thin films were indicated through photoluminescence (PL) measurements. The outcome of this project strongly suggests that the proposed approach of fabricating flexible solar cells by remote epitaxy and 2D materials-based layer transfer (2DLT) processes is indeed an auspicious path for the integration of solar cells with energy storage systems.