MBE-Grown <tex-math notation="LaTeX">β </tex-math> -Ga₂O₃-Based Schottky UV-C Photodetectors With Rectification Ratio ~10⁷

In this letter, we demonstrate high-performance vertical solar-blind Schottky photodetectors on MBE-grown homoepitaxial (010)-oriented β-Ga 2 O 3 films. The structure, consisting of (100 nm) β-Ga 2 O 3 /(60 nm) n ++ β-Ga 2 O 3 , was grown on a Fe-doped insulating (010) β-Ga 2 O 3 substrate. Ni/Au and indium were used as the Schottky and Ohmic contacts, respectively. The devices exhibited a rectification ratio of ~10 7 with turn-on voltage ~1 V and an ideality factor of 1.31. The extracted Schottky barrier height was 1.4 eV. The photodetectors showed low dark current of 0.3 nA at 5 V with a photo-to-dark current ratio of ~10 2 at 0 V. The devices exhibited a zero-bias responsivity of 4 mA/W at 254 nm corresponding to an external quantum efficiency ~3 %, with a UV-to-visible rejection ratio >10 3 , showing true solar-blind operation. The transient response of the devices indicated rise/fall times of ~100 ms. Temperature-dependent current-voltage characteristics agree with the thermionic emission model.