This study presents the morphological, electrical, and photosensitive behavior properties of the Al/(NaYF 4 :Yb,Er)/p-Si structure. The (NaYF 4 :Yb,Er) used as an interfacial layer was deposited on a p-Si semiconductor using the thermal evaporation method. The surface morphological properties of the evaporated interfacial layer were examined using scanning electron microscopy and atomic force microscopy. The ideality factor of the structure increases from 3.58 at 320 K to 8.16 at 100 K with decreasing temperature, while the barrier height decreases from 0.80 eV at 320 K to 0.31 at 100 K with decreasing temperature in the same temperature range. The photosensitive behavior of the fabricated structure were investigated using UV-A lamp with 350 nm wavelength. The spectral responsivity, photosensitivity, and detectivity values for the Al/(NaYF 4 :Yb,Er)/p-Si structure were found to be 0.525 A.W−1, 2841.38, and 2.16 × 1011 Jones, respectively.