Nano-gold via laser ablation in liquid at different laser energies on porous silicon for photodetector application

This study presents the preparation and characterization of an Au-NPs/PS photodetector. Au nanoparticle was synthesized through pulsed laser ablation in water, whereas porous silicon substrate was produced using a photo-assisted electrochemical etching. The optical, structure, and electrical properties of Au-NPs/PS devices as a function of laser energy are investigated. X-ray diffraction result shows peaks related to a gold cubic structure in the synthesized sample, indicating the formation of Au nanoparticles deposited on porous silicon. The field emission scanning electron microscopy analysis demonstrated that the particles mostly presented a spherical morphology. The gold nanocolloids exhibited distinct surface plasmon resonance peaks within the wavelength range of 500-560 nm and demonstrated enhanced absorption when the laser energy was increased. The optical characteristics indicate that the optical bandgaps of the Au nanoparticles produced at laser energies of 400, 500, 600, 700, and 800 mJ were measured to be 2.10, 2.01, 1.97, 1.98, and 1.99 eV, respectively. The optoelectronic properties show that the maximum responsivity was 0.118 A/W at a wavelength of 510 nm for the Au-NPs/PS photodetector fabricated at 700 mJ. The Au NPs/PS devices created in this work, which combine Au NPs with porous Si, exhibit great potential for use as high-efficiency photodetectors.