Synthesis of Au/Si hybrid nanostructures with tuned optical properties via ultra-short laser pulses for in-Situ nanostructures generation (ULPING)

Abstract

The research was based on nano-structuring of gold coated silicon and forming a layered Au/Si hybrid nanostructures with tuned opto-electrical properties. We employed Ultra-short Laser Pulses for In-Situ Nanostructure Generation (ULPING), a novel method for synthesizing the nano hybrid structured substrates. The variation in irradiation (power) and patterning or scanning (pitch and scan speed) parameters of the laser was done in order to create the samples. The morphological and material characterization analysis was performed using SEM, EDX and XPS which confirmed the formation of hybrid Au/Si nanostructures with SiO<inf>2</inf> nanocoating. The optical properties of the structure were evaluated using the diffuse reflectance spectroscopy and the electrical properties of the composite structure was done using a 4-point probe method. We saw an enhanced band gap for all the samples in comparison with Au–Si control samples. Also, by changing the laser pulses parameters, wide range of variations in the optical and electrical properties were observed. The band gap of the hybrid nanostructured layer (HNL) was also evaluated using XPS and the band offset was determined for the nanostructured composites. © 2023 Elsevier B.V.