Vertically oriented ReS _{2(1− x )} Se _{2 x} nanosheet-formed porous arrays on SiO ₂ /Si substrates for ultraviolet-visible photoelectric detection

Rhenium (Re)-based transition metal dichalcogenides (TMDs) have excellent in-plane anisotropic optical and electrical properties. However, their distorted octahedral (1T') structure and weak interlayer coupling easily lead to anisotropic and out-of-plane growth, which makes it particularly difficult to prepare large-area Re-based TMD continuous porous films on SiO₂/Si substrates. In this work, ReS₂ films are synthesized on SiO₂/Si substrates by using tellurium (Te) powder-assisted chemical vapor deposition, and then the films are selenized to synthesize a series of continuous large-area ReS_2(1-x)Se_2x (x = 0, 0.34, 0.56, 0.84, and 0.91) nanosheet-formed porous films. Furthermore, prototype ReS_2(1-x)Se_2x photodetectors with different Se compositions are fabricated. The surface morphology, high quality crystallization and compositions are confirmed by various characterization techniques. The ReS_2(1-x)Se_2x photodetectors based on these films show excellent ultraviolet-visible (UV-vis) spectral responses and self-powered characteristics. The response time is faster, and the photocurrent increases with the Se composition. Due to the Schottky barrier generated by the Ag-ReS_2(1-x)Se_2x interface, the device without bias voltage has a superior responsivity (121.9 mA W^-1), high detectivity (5.27 × 10¹² Jones), good on/off ratio (1.2 × 10³) and fast response time (rising/decay times, 30/60 ms) under 365 nm light irradiation. This simple and controllable method opens up a new way to produce high-quality vertically oriented ReS_2(1-x)Se_2x porous arrays on SiO₂/Si substrates for next-generation application in UV-vis photodetectors.