Defect-state and electronic-structure modulation of β-Ga2O3 thin films via Zn/N Co-doping toward deep-ultraviolet optoelectronic materials

β-Ga 2 O 3 , an ultra-wide bandgap semiconductor, holds great promise for next-generation deep-ultraviolet (DUV) optoelectronics. Here, we demonstrate a Zn/N co-doping strategy to modulate the defect states and optical/electronic structure of β-Ga 2 O 3 thin films prepared by RF magnetron co-sputtering, followed by rapid thermal annealing. Structural and spectroscopic analyses reveal that Zn incorporation and N-related bonding modify lattice expansion, oxygen-defect-related spectral components, and near-surface electronic states, accompanied by a modest bandgap variation from 4.75 eV to 4.64 eV. The films exhibit smooth morphology, high optical transparency (>90% in the visible range), and Zn-dependent defect modulation. A key advancement is the sputtering-based co-doping design that fixes the N 2 flow while tuning Zn incorporation, enabling systematic investigation of Zn-dependent defect and band-structure modulation under a constant nitrogen-supply condition. This approach provides materials-level insight into dopant-dependent defect-state and electronic-structure modulation in sputtered β-Ga 2 O 3 thin films, offering a useful basis for future DUV-relevant optoelectronic material design.