Au/Germanium_{1 − x}Bismuth_x Schottky Diode for Self‐Driven, High Detectivity, and High Responsivity Near‐Infrared Broadband Photodetectors

Abstract Metal‐semiconductor Schottky diode structures play a crucial role in the development of optoelectronic devices. In recent years, Schottky photodiode‐based photodetectors utilizing molybdenum disulfide (MoS₂) have garnered significant attention and are among the most extensively researched options. However, MoS₂ has a notable limitation: its low light absorption in the near‐infrared (NIR) spectrum results in reduced responsivity compared to the visible spectrum. To address this issue and achieve high responsivity, high detectivity, and a broad spectral response for NIR photodetectors, a GeBi‐based Au/Ge_{1 − x}Bi_x Schottky diode photodetector for the first time is proposed. By varying the doping concentration of Bi (x) and subsequently regulating the light absorption of the Ge_{1 − x}Bi_x films in the NIR band, the Ge_0.874Bi_0.126 photodetector is identified and fabricated with an optimal Bi doping concentration of 12.6%. Testing revealed that within the 800–1200 nm wavelength range, the photodetector exhibits a responsivity range of 2.47 –519.7 AW⁻¹ and a detectivity range of 3.56 × 10¹¹ Jones to 1.6 × 10¹³ Jones. In contrast to most Schottky diode‐based NIR photodetectors, which typically respond to a narrow optical spectrum, the results demonstrate that the photodetector maintains high responsivity and detectivity across the entire 800 to 1200 nm range.