Temperature Optimized β-Ga ₂ O ₃ Solar-Blind Ultraviolet Photodetectors Fabricated by PLD for Communication and Imaging Applications

The influence of substrate temperature on the structural, morphological, optical, and optoelectronic properties of β-Ga 2 O 3 thin films grown on c -plane sapphire by pulsed laser deposition (PLD) is systematically investigated in this work. Comprehensive characterization using XRD, AFM, XPS, and UV–vis spectroscopy reveals that increasing the substrate temperature drives the transition from an amorphous phase to a highly oriented (−201) β-Ga 2 O 3 structure, accompanied by changes in surface morphology, lattice strain, and defect states related to oxygen vacancies. Metal semiconductor metal photodetectors fabricated on these films exhibit temperature dependent dark current, photocurrent, response speed, and the ratio of photocurrent to dark current (PDCR), all of which show a strong correlation with the defect evolution and crystallinity of the films. Devices grown at moderate temperatures achieve the optimal balance between defect-assisted carrier generation and suppressed leakage pathways, yielding high responsivity, PDCR values above 10 3, and fast transient response. Based on these optimized characteristics, a deep ultraviolet (UV) optical communication link and a proof of concept UV imaging system were successfully demonstrated. These results provide important insights into the defect structure performance relationships of PLD grown β-Ga 2 O 3 films and offer practical guidelines for engineering high performance solar-blind photodetectors for advanced communication and imaging applications.