Controllable growth of wafer-scale two-dimensional PdS2xSe2(1-x) nanofilms with fully tunable compositions for high-performance photodetectors

Abstract

Two-dimensional (2D) noble transition-metal dichalcogenide materials (NTMDs) have garnered remarkable attention due to their intriguing properties exhibiting potential applications in nanoelectronics, optoelectronics, and photonics. The electronic structure and physical properties of 2D NTMDs can be effectively modulated using alloy engineering strategy. Nevertheless, the precise growth of wafer-scale 2D NTMDs alloys remains a significant challenge. In this work, we have achieved the controllable preparation of wafer-scale (2-inch) 2D PdS_2xSe_2(1-x) nanofilms (NFs) with fully tunable compositions on various substrates using pre-deposited Pd NFs assisted chemical vapor deposition technique. High-performance photodetectors based on the PdS_2xSe_2(1-x) NFs were fabricated, which exhibit broadband photodetection performance from visible to near-infrared (NIR) wavelength range at room temperature. Significantly, the PdS_0.9Se_1.1-based photodetectors display a responsivity up to 0.192 A W⁻¹ and a large specific detectivity of 5.5 × 10¹¹ Jones for 850 nm light, enabling an excellent high-resolution NIR single-pixel imaging (SPI) without an additional filtering circuit. Our work paves a new route for the controlled synthesis of wafer-scale and high-quality 2D NTMDs alloy NFs, which is essential for designing advanced optoelectronic devices.