Controlled optical properties via chemical composition tuning in molybdenum-incorporated β-Ga2O3 nanocrystalline films

Highlights: • Designing Mo-doped Ga₂O₃ films with controlled optical properties is reported. • Molybdenum was found to significantly affect the structure and optical properties. • Low Mo-content (≤4 at%) results in the formation of single-phase β-Ga₂O₃ films. • Higher Mo-content results in amorphous Ga-Mo-O films. • Chemically-induced high variability in the band gap in Ga-Mo-O is demonstrated. An approach is presented to design refractory-metal incorporated Ga₂O₃-based materials with controlled structural and optical properties. The molybdenum (Mo)-content in Ga₂O₃ was varied from 0 to 11 at% in the sputter-deposited Ga-Mo-O films. Molybdenum was found to significantly affect the structure and optical properties. While low Mo-content (≤4 at%) results in the formation of single-phase (β-Ga₂O₃), higher Mo-content results in amorphization. Chemically-induced band gap variability (E_g ∼ 1 eV) coupled with structure-modification indicates the electronic-structure changes in Ga-Mo-O. The linear relationship between chemical-composition and optical properties suggests that tailoring the optical-quality and performance of Ga-Mo-O films is possible by tuning the Mo-content.