<p>In this work, preparation of FeS₂ by laser-assisted chemical bath deposition (LACBD) method was demonstrated. The effect of using laser exposure via chemical deposition on the structural, optical, and electrical properties of FeS₂ thin films was studied. The scanning electron microscope investigation confirm that the particle size increases after using laser exposure during film deposition and the nanoflowers morphology was observed. The energy dispersive X-ray studies show that the deposited films have polycrystalline pyrite structure and the film’s stoichiometry was enhanced when laser used. The X-ray diffraction (XRD) investigations reveal that the film crystallinity was improved for film deposited with laser exposure. Scanning electron microscope (SEM) investigation shows formation of spongy-like structure for film deposited with laser exposure. The optical energy gap of the FeS₂ film decreases from 2.62 to 2.38&#xa0;eV when laser exposure used during deposition process. The electrical properties of the n-FeS₂/p-Si heterojunctions confirm that the junction characteristics are improved when laser exposure used and the ideality factor was found to be 3 and 1.6 for heterojunction prepared without and with laser exposure, respectively. The spectral responsivity of the photodetector fabricated with laser was improved after using laser exposure, it increases from 0.55 to 0.67&#xa0;A/W at 770&#xa0;nm. The highest detectivity and external quantum efficiency were 1.3 × 10¹² Jones and 72% at 770&#xa0;nm, respectively, for photodetector fabricated with laser exposure.</p>