Plasmonic Effects in Porous Silicon for Applications in Optoelectronics and Medical Physics

Abstract

Porous silicon (pSi) has attracted considerable attention due to its unique structure, high surface area, and optical properties, which make it suitable for sensors, photonic devices, and medical applications. However, its natural photoluminescence is weak, its catalytic performance is limited, and its conductivity under light is relatively low. This project aimed to overcome these limitations by embedding gold nanoparticles (AuNPs) into the porous structure to take advantage of plasmonic effects, particularly localised surface plasmon resonance (LSPR).

To achieve this, I used four different fabrication methods: anodization, spin coating, ultrasonic impregnation, and electroless plating. These approaches allowed the AuNPs to be positioned both on the surface and deep inside the pores of the silicon. The result was a noticeable improvement in several areas, including enhanced photoluminescence, stronger photothermal effects, more efficient hydrogen production from methanol, and electrical conductivity under light exposure.

I used techniques such as FTIR, Raman spectroscopy, and photoluminescence measurements to study how the plasmonic effects influenced the material’s properties. Photocatalytic activity was assessed by measuring hydrogen generation, and photoconductivity tests were carried out to evaluate the potential for light-based electronic applications.

What makes this work stand out is that it focuses on embedding gold nanoparticles inside the nanochannels, rather than just on the surface, which most studies have done. This internal placement leads to stronger light material interactions and better performance across multiple functions. These findings open up new possibilities for using gold-impregnated porous silicon in advanced technologies such as optical sensors, hydrogen fuel systems, and medical treatments like photothermal therapy.