Thermophysical Characteristics of the Porous Silicon Samples Formed by Electrochemical, Chemical and Combined Etching Methods

The article addresses the thermophysical properties of porous silicon (PS) samples produced through electrochemical (EC), metal-assisted chemical (MACE), and combined (MACE + EC) etching methods. The PS/MACE+EC sample's thermophysical properties exhibited higher values than both the PS/EC and PS/MACE. The energy activity associated with the process of water splitting on the surface of porous silicon (PS) formed by the metal-assisted chemical etching (MACE) combined with the electrochemical etching (EC) method is found to be more significant compared to the PS samples prepared using only EC or MACE techniques. The combined MACE/EC method is considered the most effective technique for obtaining PS with a nanoporous silicon surface, which has the highest energy activity in water-splitting processes. The activation energy required for water splitting, denoted as Ea (PS/MACE+EC), exhibits a higher value compared to the activation energies observed for the Ea (PS/EC) and Ea (PS/MACE) samples. The inclusion of nickel (Ni) particles within the pores of porous silicon (PS) serves to stabilize the thermophysical properties of the material. Consequently, this prevents substantial alterations in the thermal characteristics of PS compared to PS without nickel in its pores. The samples containing nickel (PS/MACE) and PS/MACE+EC exhibit long-term preservation of their energy activity (Ea) for one year. This phenomenon occurs due to the presence of nickel-containing nanopores within the samples. The article additionally examines the thermophysical properties of porous silicon (PS) in comparison to crystalline silicon (c-Si) and powdered silicon (powder-Si).