Graphene-enhanced (GaAs/InP) Schottky solar cells and current degradation due to proton irradiation in space use

This study investigates the degradation of GaAs, InP, and Si Schottky solar cells under proton irradiation, representative of the lunar environment. Using a suite of models for short-circuit current degradation, barrier height shift, and thermionic emission loss, we assess the photovoltaic viability of each material across extended mission durations. Our results confirm the exceptional radiation tolerance of InP, moderate endurance of GaAs, and significant vulnerability of Si to proton-induced performance loss. A major innovation is the proposed use of graphene as a replacement for traditional metal contacts in Schottky cells. Simulations show that graphene-contacted devices exhibit both higher initial current density and significantly reduced radiation degradation, particularly in GaAs. These insights directly support the power system requirements of upcoming Artemis lunar missions and future Mars expeditions, where low-mass, high-reliability, radiation-hardened photovoltaic technologies are essential. The findings guide future development of ultralight, graphene-enhanced Schottky solar cells optimized for deep-space environments.