Bias-Tuned Selective Spectral Response High-Performance Ga₂O₃/GaN Heterojunction Ultraviolet Photodetector

β-Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> films were successfully fabricated using the GaN thermal oxidation method, and Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>/GaN heterojunction ultraviolet photodetectors were constructed with varying electrode parameters, including length, width, and electrode spacing. Under optimized electrode parameters, the detector demonstrates an exceptionally low dark current, with a value of just 63.2 fA at a 10V bias. Under 33 μW/cm² ultraviolet light illumination, the detector demonstrates a high light-to-dark current ratio exceeding 10⁶. By adjusting the thickness of the β-Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> light-absorbing layer to enhance ultraviolet light absorption and reduce carrier recombination, the detector achieves a responsivity of up to 3061 A/W and a detectivity exceeding 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">15</sup> Jones. Additionally, by tuning the applied bias, the detector enables adjustable control over both the solar-blind ultraviolet single-band and solar-blind-near ultraviolet dual-band response spectra. These research findings provide important theoretical support and experimental basis for the optimized design and application of high-performance ultraviolet photodetectors.