Scandium-Engineered GaN Alloys and Superlattices: Multiscale DFT and SCAPS-1D Design for High-Efficiency Optoelectronic Solar Cells

This investigation aims to investigate scandium-doped gallium nitride (Sc-doped GaN) alloys (x = 0.25, 0.50, 0.75) in hexagonal structure and (GaN)1/(ScN)2/(GaN)2/(ScN)2 superlattices for high-efficiency optoelectronic solar cells using multiscale DFT and SCAPS-1D simulations. Our computational analysis confirms the energetic stability of all investigated compounds. Electronic structure calculations reveal semiconducting behavior with tunable bandgaps ranging from 1.7 to 2.7 eV, positioning these materials as promising candidates for optoelectronic applications. Optical characterization demonstrates significant absorption across the visible to ultraviolet spectrum, making these compounds particularly suitable for photovoltaic applications. Device simulations of Sc-doped GaN-based solar cells yielded remarkable performance metrics, achieving a maximum power conversion efficiency of 14.5%. Notably, the devices exhibited an exceptional fill factor of 86%, indicating highly efficient carrier extraction and transport properties. These findings establish Sc-doped GaN and its related superlattice structures as viable materials for next-generation high-efficiency solar cell technologies, combining optimal electronic band structure with superior optical absorption characteristics.