Construction of a β-Ga2O3-based metal–oxide–semiconductor-structured photodiode for high-performance dual-mode solar-blind detector applications†
Sensitive, high photoresponse and energy-saving detectors are urgently required to monitor solar-blind UV signals. The impressive advantages of Ga2O3 in this field give rise to extensive research and studies. A high-performance dual-mode β-Ga2O3 metal–oxide–semiconductor (MOS)-structured photodiode solar-blind detector is introduced. The device shows a rectifying ratio of 2 × 103 at ±10 V with a low reverse leakage current of 1.05 pA. Under 1.1 μW cm−2 254 nm light illumination, it provides a specific detectivity (D*) of ∼1013 Jones, a high responsivity (R) of 189.89/3.96 A W−1 and a high external quantum efficiency (EQE) of 92 879%/1936% at 10/−10 V, suggesting a high-resolution and sensitive detection in the dual operating (photoconductive/depletion) mode. At zero bias, it exhibits an ultralow dark current of 4.2 pA, an R of 33.48 mA W−1, an EQE of 16.37% and a D* of 1.83 × 1011 Jones, yielding a self-powered operation owing to the enhanced built-in electrical field. Moreover, at ±200 V, the device still avoids breakdown and displays an R of 3930.55 A W−1 and a D* of 1015 Jones, allowing harsh environmental operation. In addition, no obvious degeneration was observed after two months storage. The dual-mode photodiode promises to perform solar-blind detection along with sensitive, stable and self-powered performances.