Deposition of Gold Nanoparticles on Silicon in the Pulse Mode of Electrolysis in a DMSO Solution
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DEPOSITION OF GOLD NANOPARTICLES ON SILICON IN THE PULSE MODE OF ELECTROLYSIS IN A DMSO SOLUTION М. V. Shepida,1,2 О. І. Kuntyi,1 О. Ya. Dobrovets’ka,1 S. А. Kornii,3 and Yu. І. Eliyashevs’kyi4
UDC 621.35
We study the deposition of gold nanoparticles (AuNPs) on a surface of silicon in the pulse mode of electrolysis in dimethyl sulfoxide solutions of 2–8 mM HAuCl4 under the potentials E = (– 1.6) – (– 2.2) V. It is shown that, in the course of electrodeposition, we observe the predominant 2D filling of the substrate surface with deposits, ranging from the nanosized discrete particles to nanostructured porous films. It is shown that the geometry of AuNPs is mainly affected by the cathode potential, the concentration of ions of the reduced metal, and the duration of electrolysis. It is also demonstrated that gold nanoparticles 50–100 nm in size are formed in a medium of an organic aprotic solvent. We present the results of atomic-force and scanning electron microscopies and the histograms of distributions of particles in sizes depending on the conditions of electrolysis. Keywords: gold nanoparticles, silicon, pulse electrolysis, DMSO.
Introduction The procedure of deposition of nanoparticles of silver, gold, and platinum metals (nano-M) on silicon is one of the methods used for the modification of the surfaces with an aim of formation of silicon nanostructures and getting materials with new properties. In particular, the nano-M/Si nanostructures serve as initial for the formation of nanoporous surfaces and nanowires [1, 2] and the creation of high-sensitive sensors [3, 4]. The nature of the deposited metal and the geometry of its structural particles strongly affect the procedure of etching of silicon and, hence, its porosity [1, 2, 5]. The property of supersensitivity of the sensors mainly depends on the shapes and sizes of the deposited metallic nanoparticles (MNP) [3, 4, 6]. This is why the problem of controlled formation of the geometry of these nanoparticles is quite important. As the most promising methods of fixed deposition of MNP on the silicon surface, we can mention galvanic substitution [7–9] and electrolysis [10–15]. The first method is technologically simple but the second method offers broader possibilities for getting the nanostructures of metals with required morphologies. In the last decade, the attention of the researchers in the field of electrodeposition of precious metals is mainly concentrated on the deposition of gold nanostructures on the silicon surfaces [10, 14, 15]. This is explained, first of all, by the high chemical stability of AuNPs. The compositions of electrolytes and, in particular, very low concentrations of ions of deposited metals and high values of current densities (electrode potentials), are often similar to those observed in the case of application of the metal substrate. However, the fact that the resistance of 1 2 3 4
“L’vivs’ka Politekhnika” National University, Lviv, Ukraine. Corresponding author; e-mail: [email protected].
Karpenko Physicomechanical Institute, U
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