High sensitivity of UV photodetector based on SnO2-ZnO/P-Si heterojunctions prepared by hydrothermal method

This study aimed to fabricate an ultraviolet (UV) photodetector by using nanocomposite films of tin oxide (SnO₂) and zinc oxide (ZnO) prepared through the hydrothermal method. X-ray diffraction analysis revealed that the films exhibited polycrystalline structures, with crystallite sizes of 11.55 nm for ZnO and 6.87 nm for SnO₂. Crystallite size decreased because of the incorporation of ZnO into the SnO₂ lattice. Field-emission scanning electron microscopy images demonstrated that the nanoparticles possessed a spherical shape, and their morphology did not change after mixing ZnO and SnO₂. Energy-dispersive X-ray spectroscopy confirmed the purity of the nanocomposite films and the lack of foreign particles or impurities. Optical measurements indicated improved optical transmittance and increased energy band gap with high ZnO ratios, reflecting the influence of nanocomposite formation on the films’ optical properties. Hall effect measurements showed that all the films exhibited n-type conductivity. I–V measurements revealed Schottky’s behavior in the mixed films, with a considerable and rapid increase in photocurrent upon UV light exposure. The films demonstrated exceptional sensitivity of 1082% and a quantum efficiency of 71.01% at a 10% ZnO mixing ratio, as well as fast rise and fall times of less than one second. These findings highlight the potential of SnO₂-ZnO nanocomposites for advanced applications in UV detection, environmental monitoring, and optoelectronic device development.