Electrochemical Etching Methods for Producing Porous Silicon

Abstract

Porous silicon produced by electrochemical etching of silicon has become one of the most popular materials used in many scientific disciplines as a result of its outstanding and unique set of chemical and physical properties and cost-competitive fabrication processes. To understand the electrochemical mechanisms taking place in the course of the etching of silicon is a key factor to control and modify the structure of this versatile porous material. This makes it possible to produce a broad range of structures, which can range from a porous matrix to arrays of nanowires. These structures are unique and bring new opportunities for multiple research fields and applications such as biotechnology, medicine, optoelectronics, chemistry and so forth. This chapter is aimed at compiling and summarising the fundamental aspects behind the production of porous silicon structures by electrochemical and metal-assisted etching of silicon wafers. Our objective is to provide a simple but detailed overview about the fabrication process of porous silicon, with special emphasis on the different fabrication conditions and geometric and morphological features of the resulting silicon nanostructures.

Enhanced titanium dioxide photocatalyst embolized on micropores silicon wafer: an experimental approach

“…As illustrated in the tabulated results, the k obs was higher when using the composite prepared using the electrochemical deposition method. The present findings seem to be consistent with a previous study by Santos and Kumeria 25 for the MB degradation. Since the active sites are responsible for producing free radicals, with the increase of adsorbed MB in the active sites, a quicker photodegradation rate is achieved.…”

“…Therefore, preparing the surface of silicon before the deposition of TiO 2 is an important step. 25 Figure 1 shows the surface of the silicon wafer before and after the electrochemical etching assisted with laser projection. As shown in Fig.…”

“…Finally, the Si is etched away from the silicon wafer surface during the reaction and pores were formed on the surface of the silicon wafer as represented in Eqn (6). 25…”

Glioblastoma Homing Photodynamic Therapy Based on Multifunctionalized Porous Silicon Nanoparticles

“…We prepared GBM homing nanoparticle formulation (SIWV-pSiNP­(ICG)) by functionalizing SIWV peptides on the surface of pSiNP-incorporating ICG in the pore (Figure a). The pSiNPs were prepared by the electrochemical etching of a high boron-doped-p ++ type silicon wafer, and ICG was incorporated within pSiNP via a calcium-assistant loading method using an ultrasonic bath. − The ICG-loaded pSiNP formulation (pSiNP­(ICG)) was functionalized with SIWV peptides via a poly­(ethylene glycol) (PEG, M.W. = 5 kDa) linker.…”

Mesoporous Silicon Particles Favor the Induction of Long-Lived Humoral Responses in Mice to a Peptide-Based Vaccine

“…The SEM images showed that the oxidized PSiP had irregular flat discoid shape ( Figure 1 a), and the statistical analysis of a SEM micrography of 150 particles determined a size distribution of 3 ± 1 µm ( Figure 1 b) and a thickness of ~400 nm. The sonication cycles, including the time and number of cycles, are the main factors in the resulting shape and particle size [ 21 , 22 ]. Moreover, the SEM analysis demonstrated that the PSiP surface presented homogeneous, cylindrical porous structures ( Figure 1 c) with an average pore size of 40 nm ( Figure 1 d); this confirms the presence of a mesoporous material.…”