Improved spectral responsivity of porous silicon after the deposition of palladium nanoparticles via laser ablation at different laser energies

In this work, palladium (Pd) nanoparticles (NPs) were synthesized using laser ablation in liquids (LAL) at laser energies of 360, 660, and 800 mJ and a laser wavelength of 1064 nm with 200 pulses per shot. The Pd nanoparticle suspension deposited on porous silicon (PS) was investigated. X-ray difraction (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 nm, and energy gap values of X2.35, 2.56, and 2.75 eV were calculated for the laser energies 360, 660, and 800 mJ, respectively. The electrical properties, including I -V and Iph-V ; of the Al/PS/Si/Al and Al/ Pd NPs/PS/Si/Al heterojunctions were calculated from I -V 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.