We investigated the multifaceted gas sensing properties of porous silicon thin films electrodeposited onto (100) oriented P-type silicon wafers substrates. Our investigation delves into morphological, optical properties, and sensing capabilities, aiming to optimize their use as efficient gas sensors. Morphological analysis revealed the development of unique surfaces with distinct characteristics compared to untreated sample, yielding substantially rougher yet flat surfaces, corroborated by Minkowski Functionals analysis. Fractal mathematics exploration emphasized that despite increased roughness, HF/ethanol-treated surfaces exhibit flatter attributes compared to untreated Si sample. Optical approaches established a correlation between increased porosity and elevated localized states and defects, influencing the Urbach energy value. This contributed to a reduction in steepness values, attributed to heightened dislocations and structural disturbances, while the transconductance parameter decreases. Simultaneously, porosity enhances the strength of electron‒phonon interaction. The porous silicon thin films were further tested as effective gas sensors for CO₂ and O₂ vapors at room temperature, displaying notable changes in electrical resistance with varying concentrations. These findings bring a comprehensive exploration of some important characteristics of porous silicon surfaces and established their potential for advanced industrial applications.

In this study, we investigated the morphology of synthesized Cu/Ni nanoparticles in trace of carbon sources by the co-deposition process of RF sputtering and RF-PECVD methods and localized surface plasmon resonance of CO gas sensing of Cu/Ni nanoparticles. The surface morphology was studied by analyzing 3D micrographs of atomic force microscopy using image processing techniques and fractal/multifractal analyses. The MountainsMap® Premium software with the two-way ANOVA (Variance analysis) and least-significant differences tests were used for statistical analysis. The surface nano-patterns have a local and global particular distribution. Experimental and simulated Rutherford backscattering spectra confirm the quality of nanoparticles. Then, prepared samples were exposed to CO gas flue to study their gas sensor application using the localized surface plasmon resonance method. Increasing the Ni layer over Cu one shows an interesting result in both morphology and gas sensing sides. Advanced stereometric analyses for the surface topography of thin films in conjunction with Rutherford backscattering spectrometry and Spectroscopic analysis make a unique study in the field.