Broadband-responsive backside-illuminated avalanche photodiode passivated by an organic ferroelectric-induced carrier accumulation layer

The design and fabrication of backside-illuminated photodetectors still face challenges in achieving full-spectrum detection ranging from ultraviolet to near-infrared wavelengths, a low leakage current, and mass- and cost-effective production. To overcome these difficulties, we present the first backside-illuminated ferroelectric-induced avalanche photodiode in which the silicon substrate is completely removed from the incident surface and a transparent organic ferroelectric-induced carrier accumulation layer for passivation is processed with a fixed charge density of - 3.75 × 10¹¹cm^-2. This device demonstrates high external quantum efficiency exceeding 45% over the range of 300-950 nm, reaching 70% at 905 nm, while maintaining an ultralow leakage current of approximately 10 pA. The organic ferroelectric passivation method employed is compatible with low-cost chip-on-board packaging, offering a superior solution for broadband photodetector applications.