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.