Phosphorus-Doping Enhanced Self-Powered Photoelectric Performance of SnS2-Based Schottky Junction Photodetectors

SnS₂, a promising candidate for high-performance photodetectors (PDs), encounters challenges as high dark current and poor stability in practical applications. Herein, pristine SnS₂ (P₀SS) and phosphorus (P) doped SnS₂ single crystals (P₁SS, P₂SS) are synthesized and implanted into devices with an asymmetric electrode contact structure, which demonstrate self-powered photoelectric responses. At 0 V, P-doped SnS₂ PDs exhibit significant broadening of the response spectrum. Meanwhile, the P₂SS device achieves the highest responsivity of 57.4 mA W⁻¹ and specific detectivity of 1.22 × 10¹¹ Jones at 365 nm, and has superior long-term cyclic stability. At 1 V, the dark current of P₂SS is significantly lowered, and the on-off ratio is about two orders of magnitude higher than those for the other two at 515 nm. The self-powered phenomenon of the three PDs here is attributed to the asymmetric Schottky barriers at the two gold/SnS₂ interfaces of the source and drain electrodes. The enhanced photoelectric response of the P-doped SnS₂ PDs can be due to the lowered conductivity and higher exciton separation efficiency by the compensation doping. This work offers a promising pathway for optimizing the optoelectronic detection capability of future portable devices.