DUV-NIR dual-band photodetector based on Ga2O3/GaAs heterogeneous junctions

Abstract

In this work, we demonstrate dual band vertical heterojunction photodetector realized by integrating Ga₂O₃ with n-type GaAs. For comparison, we fabricated Ga₂O₃/GaAs Heterogeneous junction metal-semiconductor-metal photodetectors (MSM PD). The Ga₂O₃/GaAs devices show two distinct detection peaks in spectral responsivity, one at 255 nm and another at 830 nm. Under the ultraviolet (UV) light illumination at 254 nm, at a biasing voltage of 10 V, an ultra-low dark current (I_dark) of 3.5 × 10⁻⁹ A, a high photo-to-dark current ratio (PDCR) of 8.7 × 10², a responsivity(R) of ∼25.8 A/W, a specific detectivity (D∗) of 4.2 × 10¹³ Jones are achieved. And PDCR is 2.7 × 10², R is ∼0.45 A/W and D∗ is 7.3 × 10¹¹ under the infrared(IR) light illumination at 830 nm, at the same biasing voltage of the device. Compared to single-layer Ga₂O₃ and GaAs MSM PDs, Ga₂O₃/GaAs devices are capable of responding to the UV/IR bands simultaneously, while increasing the responsivity from 5.9 A/W to 25.8 A/W and the D∗ from 1.7 × 10¹² Jones to 4.2 × 10¹³ Jones under UV irradiation. Meanwhile, the dual-band photodetector based on Ga₂O₃/GaAs Heterogeneous junctions shows good stability and reproducibility. Our results present a new avenue for designing multifunctional photodetectors, enabling operation in complex environments.