AlInGaN 310 nm ultraviolet metal-insulator-semiconductor sensors with photo-chemical-vapor-deposition SiO2 cap layers

Al_0.25In_0.04Ga_0.71N 310 nm near solar blind ultraviolet (UV) metal-insulator-semiconductor (MIS) sensors with different SiO₂ cap layer thickness were successfully fabricated. With appropriate SiO₂ layer thickness, the dark current of AlInGaN sensors was notably suppressed from 1.88 × 10⁻⁶ to 1.91 × 10⁻⁹ A, and the photo-generated carriers still could reach the electrodes by tunneling through the thin SiO₂ layer under the illumination. It could be clearly seen that cut-off occurred at around 300/310 nm while the responses above the bandgap were flat.