Enhancingβ-Ga₂O₃-film ultraviolet detectors via RF magnetron sputtering with seed layer insertion onc-plane sapphire...

Gallium oxide (Ga₂O₃) possesses a band gap of approximately 4.9 eV, aligning its detection wavelength within the solar-blind region, making it an ideal semiconductor material for solar-blind photodetectors. This study aims to enhance the performance of Ga₂O₃ultraviolet (UV) detectors by pre-depositing a Ga₂O₃seed layer on ac-plane sapphire substrate. The x-ray diffraction and x-ray photoelectron spectroscopy analyses validated that the deposited films, following high-temperature annealing, comprisedβ-Ga₂O₃. Comparing samples with and without a 20 nm seed layer, it was found that the former exhibited fewer oxygen defects and substantially improved crystal quality. The incorporation of the seed layer led to the realization of detectors with remarkably low dark current (≤15.3 fA). Moreover, the photo-to-dark current ratio was enhanced by 30% (surpassing 1.3 × 10⁴) and the response/recovery time reduced to 0.9 s/0.01 s, indicating faster performance. Furthermore, these detectors demonstrated higher responsivity (4.8 mA W^-1), improved detectivity (2.49 × 10¹⁶Jones), and excellent solar-blind characteristics. This study serves as a foundational stepping toward achieving high-qualityβ-Ga₂O₃thin film and UV detector arrays.