Novel controlling pathway for metallic nanoparticles by laser assisted ion-reduction process

In this work, the morphological and plasmonic features of the AgNPs which formed by ion-reduction process was carried out extensively. The application of the laser beam during the ion- reduction process has significant effect in the reconstruction of the formed AgNPs with small dimensions and non-frequent morphologies, according to the laser illumination intensity. For non-illumination process the deposited form of the AgNPs appear aggregated into cluster of layer AgNPs size due to the chemical reaction at Si interface, the AgNPs sizes varied from 0.85 to1.2 µm; while at lower laser intensity of about 250 mW/cm2 the AgNPs sizes varied from 0.1 to 1.0 µm, while at high intensity upto 400 mW/cm2 the AgNPs sizes varied from 0.05 to 0.4 µm. The hot spot dimension for non-illumination process varied from 1 to 11 nm while at low intensity of 250 mW/cm2 the hot spot dimension varied from 1to 8 nm. At high intensity upto 400 mW/cm2 , the hot spot varied from 0.1 to 14 nm. The XRD for the generated Ag nanoparticles / Si nanocrystallites, for non- illumination the grain size about 6.171 nm and SSD about 92.687 m2 /g while at low intensity of 250 mW/cm2 the grain size about 4.759nm and SSD about 120.191 m2 /g. At high intensity of 350 mW/cm2 , the grain size about 2.037nm and SSD about 280.847m2 /g uniform distributed AgNPs with minimum hot spot regions can be realized with 350mW/cm2 laser illumination intensity. This process is considerable as a novel work which can be adopted modification at the plasmonic features of metallic nanoparticles for SERs application.