# Simultaneous Electrochemical Formation of Porous Silicon and Noble NPs for Au Nucleation Sites in SERS Substrates

## TL;DR

This paper introduces a one-step method to create SERS substrates by forming porous silicon and noble metal nanoparticles simultaneously, improving reusability and spectral quality.

## Contribution

A novel one-step electrochemical strategy for creating bimetallic SERS substrates with enhanced reusability and spectral precision.

## Key findings

- HAuCl4-treated substrates achieved the highest Raman intensity.
- K2PtCl4-treated substrates showed superior spectral quality with minimal fluorescence.
- Pt-assisted substrates demonstrated stable performance over multiple cycles.

## Abstract

This study presents a one-step electrochemical etching
strategy
that enables the simultaneous formation of porous silicon (PSi) and
in situ deposition of noble metal nanoparticles (NPs), which subsequently
act as nucleation sites for gold growth to form bimetallic SERS substrates.
Three metal precursorsK2PtCl4, HAuCl4, and K2PdCl4were systematically
compared to elucidate how precursor type affects PSi morphology, nanoparticle
distribution, and subsequent gold deposition. SEM and EDS analyses
revealed distinct deposition behaviors among the metals, leading to
varied gold nucleation efficiencies and SERS enhancement levels. HAuCl4-treated substrates produced the highest absolute Raman intensity,
while K2PtCl4-treated substrates exhibited lower
intensity but superior spectral quality with minimal fluorescence
background and sharper peaks. XRD and XPS confirmed successful gold
deposition and precursor-dependent interfacial interactions, including
the formation of Pt–Au bimetallic interfaces. Reusability tests
demonstrated that the Pt-assisted substrates maintained stable performance
over multiple cycles, confirming their structural robustness and practical
feasibility. Overall, this work provides mechanistic insight into
how noble metal interfaces govern SERS spectral characteristics and
establishes a rational pathway for designing PSi-based SERS substrates
emphasizing spectral precision, reproducibility, and reusability rather
than mere sensitivity enhancement.