In this work, palladium (Pd) nanoparticles (NPs) were synthesized using laser ablation in liquids (LAL) at laser energies of 360, 660, and 800[Formula: see text]mJ and a laser wavelength of 1064[Formula: see text]nm with 200 pulses per shot. The Pd nanoparticle suspension deposited on porous silicon (PS) was investigated. X-ray diffraction (XRD) was used to determine the crystal structure. Field emission-scanning electron microscopy (FE-SEM) revealed the sponge-like structure of the PS and spherical clusters of Pd NPs within it. The optical properties of the prepared solution samples were investigated by testing the absorbance between 250–850[Formula: see text]nm, and energy gap values of ∼2.35, 2.56, and 2.75[Formula: see text]eV were calculated for the laser energies 360, 660, and 800[Formula: see text]mJ, respectively. The electrical properties, including [Formula: see text] and [Formula: see text] of the Al/PS/Si/Al and Al/Pd NPs/PS/Si/Al heterojunctions were calculated from [Formula: see text] measurements. The observed enhancement of the fabricated Pd NPs/PS is shown by the broad spectral response in the visible to near-infrared (vis-NIR) range. The increased spectral responsivity due to coating the PS surface with Pd NPs promotes using these nanostructures in photodetectors.