Vapor phase growth of two-dimensional PdSe₂ nanosheets for high-photoresponsivity near-infrared photodetectors

Palladium diselenide (PdSe₂), a stable layered material with pentagonal structure, has attracted extensive interest due to its excellent electrical and optoelectronic performance. Here, we report a reliable process to synthesize PdSe₂ via chemical vapor deposition (CVD) method. Through systematic regulation of temperature in the growth process, we can tune the thickness, size, nucleation density and morphology of PdSe₂ nanosheets. Field-effect transistors based on PdSe₂ nanosheets exhibit n-type behavior and present a high electron mobility of 105 cm²·V^-1·s^-1. The electrical property of the devices after 6 months keeping in the air show little change, implying outstanding air-stability of PdSe₂. In addition, PdSe₂ near-infrared photodetector shows a photoresponsivity of 660 A·W^-1 under 914 nm laser. These performances are better than those of most CVD-grown 2D materials, making ultrathin PdSe₂ a highly qualified candidate material for next-generation optoelectronic applications.