MBE-Grown $\beta$ -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.