High performance solar-blind photodetectors based on MOCVD grown β-Ga2O3 with hydrogen plasma treatment

Abstract The growing demand for efficient solar-blind ultraviolet photodetectors has fueled interest in the exceptional properties of β-Ga2O3. Here, solar-blind ultraviolet photodetectors with a metal-semiconductor-metal (MSM) structure are fabricated based on β-Ga2O3 thin films. The (2-01) oriented β-Ga2O3 is grown on c-plane sapphire using metal-organic chemical vapor deposition (MOCVD). Hydrogen as a shallow donor is introduced into the β-Ga2O3 surface layer selectively on the area underneath contacts by plasma treatment to enhance the ohmic contact. As a result, superexcellent performances are demonstrated, including a remarkable responsivity of 3.0×104 A/W at a wavelength of 238 nm, specific detectivity of 1.2×1017 Jones and an external quantum efficiency of 1.5×107 %. Also, faster rise and decay speed are achieved. The hydrogen plasma treatment brings fast transit time of carriers and effective gain electron injection, which are used to explain the enhancement of performance. This work highlights that hydrogen plasma treatment selectively on the area underneath contacts is an efficient strategy for achieving high-performance β-Ga2O3 solar-blind ultraviolet photodetectors.