Optimizing of porous silicon morphology for synthesis of silver nanoparticles

• Synthesis of well-controlled porous Si (PSi) morphology for silver nanoparticles (AgNPs) formation.
• Efficient method to controlling meso-pores structures size in PSi via adjusting etching current density.
• Easy fabrication way for (nanosilver/specific morphology of PSi) composite for chemical compounds detection.
• Well-organized and controlled process for silver ion reduction according to specific morphology of PSi.

A group of porous silicon (PSi) samples with different surface morphologies prepared at different etching current densities were investigated as a substrate for formation of silver nanoparticles (AgNPs). Simple dipping process of PSi in silver nitrite (AgNO3) with concentrations of 10−3, 10−2, and 5 × 10−2 M was employed to synthesize AgNPs.The p-type PSi was prepared by electrochemical etching process at different values of current densities. Three different forms of PSi morphology; meso, macro, and pillar with different roughness values 1.21, 177, 89.5, and 38.7 nm were prepared with varying the current densities 30, 60, 90, and 120 mA/cm2 respectively. The structural and surface morphology properties of samples before and after dipping in AgNO3 were studied through analyzing of scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The results show that the AgNPs sizes depend on the surface morphology and roughness of PSi. The AgNPs prepared by dipping process does not depend on the porosity of the porous layer. For meso pore-like structures the sizes of AgNPs were in the range from 0.52 to 4.09 μm for a low surface roughness, and from 0.52 to 6.83 nm for high surface roughness. For the case of macro pore-like structure which possesses the highest pore sizes and surface roughness, the AgNPs sizes vary from 0.61 to 3.42 μm. The minimum AgNPs size of about 190 nm was obtained from porous surface of pillar form.

Figure optionsDownload as PowerPoint slide