Investigation of morphology, reflectance and photocatalytic activity of nanostructured silicon surfaces

• The morphology of silicon etched is considerably influenced by AgNO3 concentration.
• An etched film consisting of two nanostructured layers was obtained for AgNO3 concentration of 0.02 M.
• The lowest reflectance (< 0.63%) in the wavelength range 200-800 nm is obtained for etching time of 15 min.
• The highest activity catalytic is observed for samples decorated with Cu nanoparticle.

One-step metal-assisted electroless chemical etching of silicon substrate in aqueous NH4F/AgNO3/HNO3 solution is investigated. The effects of etching time and AgNO3 concentration on the morphology and reflectance of etched layer are studied. It is found that the morphology and reflectance depend strongly on these parameters. The lowest reflectance is obtained for 0.009–0.01 Ω ∙ cm p-Si(100) etched in 2 M NH4F–1.89 M HNO3–0.01 M AgNO3 aqueous solution for 15 min. Indeed, the reflectance did not exceed the value of 0.63% in the 200–800 nm range. In addition, nanostructured silicon surfaces obtained through etching using this solution are decorated with copper and silver nanoparticles and their photocatalytic activity for the degradation of rhodamine B under UV and visible light irradiation is evaluated. The highest catalytic activity is observed for samples decorated with Cu nanoparticles. This is attributed to their ability to facilitate electron–hole separation and to promote electron transfer in the photocatalytic process.

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