Abstract

We investigate MoSSe/AlN heterostructures using first-principles calculations to assess their structural stability, electronic properties, and photocatalytic potential for water splitting. Six stable stacking configurations are identified, all exhibiting indirect band gaps ranging from 0.56 to 1.20 eV (PBE) and 1.03 to 1.73 eV (HSE). Biaxial strain effectively tunes the band gap energies and can induce transitions from indirect to direct band gaps or even metallic states. Applying a perpendicular electric field further modulates the band gap, with bilayer structures showing initial band gap enlargement followed by a sharp decrease, while trilayers generally exhibit a monotonic decrease, leading to potential metallization. Unstrained AA, AB, A ' A ' A ', and AB ' A configurations align favorably with water redox potentials, making them promising for photocatalytic water splitting. Our findings highlight the tunability of MoSSe/AlN heterostructures through stacking, strain, and electric fields, offering insights for designing advanced materials in nanoelectronics and renewable energy applications.