V–Ni–Te Nanocomposites for the Fabrication of Visible-Light Photodetectors

Metal tellurides are gaining significant attention owing to their unique optoelectronic properties. They are widely used in applications such as photodetectors, thermoelectric devices, and energy storage systems. In this study, crystalline VTe 2, NiTe, and V–Ni–Te nanostructures were successfully synthesized via a hydrothermal method. Structural analysis confirmed that the V–Ni–Te nanostructure exhibits a mixed-phase composition comprising both VTe 2 and NiTe. Morphological characterization revealed that VTe 2 forms nanosheet-like structures, NiTe shows nanoflower-like features, and the V–Ni–Te nanostructure presents a hybrid morphology of nanosheets with spherical nanoparticles. Raman spectra also reveal different vibrational modes of both V–Te and Ni–Te. Optical studies demonstrated a reduction in the optical band gap from 2.75 eV (VTe 2 ) to 2.54 eV (V–Ni–Te), attributed to the quantum confinement effect, supported by crystallite size analysis. The surface chemistry study confirmed the presence of V 4+, Te 2–, and Ni 2+ oxidation states, indicating the successful incorporation of each element within the composite structure. Photoresponse measurements under periodic light on/off (60 s intervals) showed a notable current response in the microampere range, with a responsivity of 4.19 μA/W and detectivity of 1.219 × 10 12 Jones. The observed fast rise and decay times further demonstrate the potential of the V–Ni–Te nanostructure for efficient broadband photodetector applications under visible light. These findings suggest the V–Ni–Te nanostructure as a strong candidate for next-generation optoelectronic and sensing devices.