Carbon Footprint and Techno-Economic Analysis of Sustainable Ge Nanomembrane Fabrication using PEELER for Space PV

Germanium (Ge) is a critical and expensive material used in high-efficiency multijunction (MJSCs) solar cells for space photovoltaics, where most of the Ge wafer serves only as mechanical support. The porous Germanium Efficient Epitaxial LayEr Release (PEELER) technique enables the fabrication of Ge nanomembranes (NMs) while allowing multiple reuses of the Ge substrate, potentially reducing both cost and environmental impact of MJSC fabrication. In this study, we provide a combined carbon footprint and cost analysis of the PEELER process. Calculations followed GreenHouse Gas (GHG) protocol, integrating stoichiometric modeling and life cycle inventory data from the literature. Results show a reduction of the global warming potential from ~80 kg CO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>e per wafer to ~15 kg CO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>e after only five reuse cycles. The cost per wafer drops from ~US $450 to ~US$90 after 5 cycles. Our study supports PEELER as a promising reuse-based strategy for sustainable and cost-effective Ge NMs fabrication in space PV applications.