High-Performance Ferroelectric Polymer Side-Gated CdS Nanowire Ultraviolet Photodetectors

An efficient ferroelectric-enhanced side-gated single CdS nanowire (NW) ultraviolet (UV) photodetector at room temperature is demonstrated. With the ultrahigh electrostatic field from polarization of ferroelectric polymer, the depletion of the intrinsic carriers in the CdS NW channel is achieved, which significantly reduces the dark current and increases the sensitivity of the UV photodetector even after the gate voltage is removed. Meanwhile, the low frequency noise current power of the device reaches as low as 4.6 × 10⁻²⁸ A² at a source-drain voltage V_ds = 1 V. The single CdS NW UV photodetector exhibits high photoconductive gain of 8.6 × 10⁵, responsivity of 2.6 × 10⁵ A W⁻¹, and specific detectivity (D*) of 2.3 × 10¹⁶ Jones at a low power density of 0.01 mW cm⁻² for λ = 375 nm. In addition, the spatially resolved scanning photocurrent mapping across the device shows strong photocurrent signals near the metal contacts. This is promising for the design of a controllable, high-performance, and low power consumption ultraviolet photodetector.