SP conceived the low temperature deposition of SiNWs idea and their exploitation into devices. He supervised the work and reviewed the manuscript. All authors read and approved the final manuscript.”
“Background Electrochemical anodizing of bulk crystalline silicon (Si) at specific conditions causes the formation of chaotic or ordered pore channels in its volume . The material formed by such artificial nanostructuring is called porous
silicon (PS). This porous morphological type of silicon presents an object of great interest of the scientific community because, in contrast to the bulk silicon, it demonstrates a number of peculiarities such as extremely developed surface, photo- and electroluminescence, and biocompatibility. Possession of these properties makes PS applicable to the areas THZ1 clinical trial of optoelectronics and display technologies, micromechanical systems, biomedicine, etc. The challenge to develop and engineer novel devices and technologies based on PS forces researchers to actively seek methods to control and manage the PS properties. One way to realize it is the incorporation of metal nanoparticles (NPs) into the pores of PS by deposition from wet solutions. Unlike dry methods (evaporation or sputtering), wet deposition provides deep penetration of metal atoms into pore channels . Moreover, wet MGCD0103 technologies are characterized by simplicity and low cost. Immersion deposition presents a less
complicated wet method of PS metallization. In contrast to electrochemical and chemical depositions, in this process, a source of the electrons for metal atoms reduction is PS itself. In aqueous solutions, the ions of metals,
which have redox potential greater than hydrogen, attract electrons from Si atoms and are reduced to the atomic form . The immersion deposition of other metals can be carried out by the use of alkaline solutions . During wet deposition, metal structures tend to grow as island films according to 17-DMAG (Alvespimycin) HCl the Volmer-Weber mechanism . Penetration of metals into PS may be easily controlled by the alternation of PS porosity . Therefore, it is possible to fabricate metal films on the outer surface of PS or metal/PS nanocomposites (NCs). Obviously, during the immersion process, the Si skeleton of PS is oxidized, and SiO2 is formed under deposited metal structures [3, 7]. The oxide’s interlayer prevents further redox LY3023414 cell line reactions between Si and metal ions, and as a result, there reduction of metal stops. Usually, to avoid the effect of oxidation, immersion deposition in the presence of fluoride species is performed [8, 9]. In this case, SiO2 removal followed by Si oxidation caused the dissolution of the PS skeleton. Proper conditions of the metal immersion deposition and PS parameters can lead to the complete conversion of PS to porous metal . The structures formed by immersion deposition of metals on PS are widely studied to be successfully applied in some technologically important areas [11–15].