Effect of Cumulative Nanosecond Laser Pulses on the Plasma Emission Intensity and Surface Morphology of Pt- and Ag-Ion Deposited Silicon

In this work, the laser induced plasma plume characteristics and surface morphology of Pt- and Ag-ion deposited silicon were studied. The deposited silicon was exposed to cumulative laser pulses. The plasma plume images produced by each laser shot were captured through a computer controlled image capturing system and analyzed with image-J software. The integrated optical emission intensity of both samples showed an increasing trend with increasing pulses. Ag-ion deposited silicon showed a higher optical emission intensity as compared to Pt-ion deposited silicon, suggesting that more damage occurred to the silicon by Ag ions, which was confirmed by SRIM/TRIM simulations. The surface morphologies of both samples were examined by optical microscope showing thermal, exfoliational and hydrodynamical sputtering processes along with the re-deposition of the material, debris and heat affected zones’ formation. The crater of Pt- ion deposited silicon was deeper but had less lateral damage than Ag- ion deposited silicon. The novel results clearly indicated that the ion deposited silicon surface produced incubation centers, which led to more absorption of incident light resulting into a higher emission intensity from the plasma plume and deeper crater formation as compared to pure silicon. The approach can be effectively utilized in the laser induced breakdown spectroscopy technique, which endures poor limits of detection.