Enhancing Gas Sensing Performance through Laser Ablation Characterization of Silver@Gold Bimetallic Nanoparticles

Abstract

This investigation analyzes the impact of a laser pulse energy set at 700 millijoules per pulse on silver, gold, and silver@gold nanoparticles deposited onto porous silicon (PS). Our primary objective is to discern optimal conditions by comprehensively evaluating their influence on structural, electrical, morphological, and optical characteristics. Employing pulsed laser ablation in liquid, an Nd:YAG laser featuring a 10-nanosecond pulse width and a 1064 nm wavelength is utilized for nanoparticle creation. X-ray diffraction analysis (XRD) is employed to affirm the crystalline growth of core-shell nanoparticles, with distinct peaks in the data confirming the presence of both Au and Ag nanoparticles. Morphological analysis reveals a robust attachment between the nanoparticles and the porous silicon layer, indicating structural stability. The UV–vis spectra exhibit a localized surface plasmon resonance (LSPR) band within the 412–521 nm range. Notably, with an increase in gold concentration, the two peaks of the LSPR band converge into a singular peak. Comparison of the photoluminescence emission spectra of the PS substrate and NPs/PS demonstrates a significant broadening of the emission band in PS,