Increasing Radiation Tolerance of InGaAs/GaAsP Quantum Well Solar Cells

Quantum well (QW) solar cells represent a promising advancement in photovoltaic technology, leveraging quantum confinement to enhance carrier generation and collection efficiency. By confining charge carriers in a reduced-dimensionality region, QW solar cells can increase the density of states at the band edges, resulting in enhanced optical absorption and improved overall performance compared to conventional bulk material solar cells. Additionally, QW structures allow for precise bandgap engineering, making them highly suitable for multijunction solar cell designs, where bandgap optimization is crucial for maximizing the efficiency of energy conversion from sunlight across different spectral regions. A significant challenge for QW solar cells, particularly for space-based applications, is their susceptibility to radiation-induced degradation. Non-ionizing energy loss (NIEL) caused by high-energy particles can lead to defects in the material structure, compromising device performance. To address this, the reduction of QW region thickness can mitigate the affected area and improve the electric field in the intrinsic region, thereby enhancing carrier capture and minimizing the effects of radiation damage. In this study, we investigate the radiation tolerance of quantum well solar cells by examining the effect of varying phosphorus (P) content in GaAsP barriers. Strain-balanced (SB) QWs with different P compositions are fabricated and verified using high-resolution X-ray diffraction (HRXRD) to confirm strain compensation and superlattice thickness. We aim to determine how varying P content influences the structural integrity and radiation tolerance of the QW solar cells. The presentation will showcase the performance of these SB QWs both before and after exposure to electron irradiation, focusing on end-of-life (EOL) performance. This investigation offers insights into optimizing QW designs for improved radiation resilience and durability in space applications.