Demonstration of GaAs-Based Photovoltaics on Acoustically Spalled Surfaces Grown by MOCVD

Abstract

This study demonstrates the potential of sonic lift-off (SLO) technology for repeatable substrate reuse in gallium arsenide (GaAs)–based photovoltaics (PVs), offering a pathway toward cost effective production for terrestrial PV applications. Single-junction GaAs solar cells fabricated on acoustically spalled substrates achieved performance metrics comparable with those grown on standard commercial substrates, exhibiting short-circuit current densities ( $J_{sc}$) of approximately 26.2–26.4 mA/cm², open-circuit voltages ( $V_{oc}$) around 1001 mV, fill factors (FFs) of 84%, and AM1.5G efficiencies near 22%. These results confirm that one reuse cycle can be realized without a performance penalty, offering a direct pathway to reducing substrate cost in fabrication. However, subsequent reuse of the substrates highlighted critical challenges, as devices fabricated from reused substrates showed significant degradation in performance ( $J_{sc}$ of 15.5 mA/cm², $V_{oc}$ of 748 mV, FF of 72%, and efficiency of 8%), primarily due to degradation of the epitaxial structure resulting from repeated spalling cycles.