Porous Silicon-Based UV Photodetectors: Enhancing Performance with Ta-Doped ZnO

In this study, we investigated the influence of defect engineering via Ta doping on the performance of ultraviolet photodetectors based on ZnO/porous silicon (PS) heterostructures. PS layers were fabricated on heavily doped p-type silicon wafers through electrochemical anodization at current densities of 5–10 mA/cm² for 15 min. Undoped and 1% Ta-doped ZnO thin films were characterized using X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. Optical measurements with a UV/VIS spectrophotometer revealed that increasing PS layer thickness and pore diameter enhances UV absorption and reduces reflectance. Notably, Ta doping improved performance by increasing absorption by approximately 2% and reducing reflectance by up to 10% in the 200–400 nm wavelength range. Electrical characterization via I–V measurements demonstrated a low dark current of 0.017 µA at 5 V for the Ta-doped device. These results indicate that precise control of PS formation combined with Ta doping significantly enhances both the optical and electrical properties of UV photodetectors.