No abstract

In this work, we fabricated an efficient macroporous silicon/gold nanoparticles (macro psi/AuNPs) hybrid structure and how well controlling of plasmonic features on macro psi/AuNPs employs them for highly sensitive detection of the very low concentration of cyanine (Cy) dyes molecules. Macro-PSi was synthesized on n-type Si wafer with 3-10 Ω. cm resistivity and 100 orientation using Photo Electro Chemical Etching (PECE) process with630 nm illumination wavelength and 30 mW/cm 2 illumination intensity. The macroPSi /AuNPs hybrid structure substrates were prepared by simple and quick dipping process of macroPSi in tetrachloroauric gold solution HAuCl 4 with different concentrations of (10

In this work, two configurations (planner and sandwich) structures of (Al/n PSi/n-Si/Al) porous silicon (PSi) gas sensor have been fabricated and tested extensively for CO 2 gas molecules. Two laser wavelength infrared and violet of (810 nm) and (405 nm) was used in the laser assisting etching process on the n-type silicon substrate. The gas detection characteristic of planner and sandwich configuration were studied under different condition. The resistance measurement, for the planner and J-V characteristic for sandwich structures, which was analyzed based on the nano-sized silicon, porosity, layer thickness, and the effective dielectric constant of the PSi layer. The SEM image of the PSi layer showed the formation pore-like structure with cylindrical and rectangular pore shape with different dimensions for infrared illuminated PSi and crossed pores-like structure with randomly distributed for violet illuminated PSi. The sensing mechanism for sandwich structure configuration is governed by the porous silicon parameters, while for planer configuration the silicon channel among the pore has a significant role in sensing process.

Mesoporous silicon (mesoPSi) layer prepared by a laser-assisted etching process in HF acid has been employed as CO 2 gas sensors. The surface morphology of mesoPSi was modified by embedding gold nanoparticles AuNPs by simple and quick dipping process in different gold salts concentrations to form mesoPSi/AuNPs hybrid structures. Morphology of hybrid structures was investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrical characteristics of the prepared gas sensor were carried out at room temperature. It was found that the nanoparticles size, shape and the specific surface area of the nanoparticle strongly influence the current-voltage characteristics. Considerable improvement was noticed in sensitivity, response and recovery times of gas sensor with decreasing incorporated AuNPs into the mesoPSi matrix.

No abstract

In this work, the influence of alloying the porous surface with uniform distributed gold nanoparticles on the characteristic porous silicon gas sensors for petroleum gas detection has been fabricated and studied extensively. Well-controlled gold nanoparticles were prepared by employing the simple dipping process of the macro porous silicon surface in diluted concentrations of HAuCl 4 salt aqueous solution. The sensing properties of the prepared porous silicon-based sensors, sensitivity response and recovery times at room temperature operating in CO gas were studied. The sensitivity of alloyed porous silicon increased from 38% to about 82% incorporation of gold nanoparticles. The lowest gas pressure detection process of CO molecules was improved from 1 mbar to 0.5 mbar. The surface alloying with rounded gold nanoparticles improved the integrated specific surface area of the alloyed porous silicon/gold nanoparticles structure, so efficient gas developed with the low-cost process.

No abstract

No abstract