Optimization of Chemical Displacement Deposition of Copper on Porous Silicon

Abstract

Copper (II) sulfate was used as a source of copper to achieve uniform distribution of Cu particles deposited on porous silicon. Layers of the porous silicon were formed by electrochemical anodization of Si wafers in a mixture of HF, C3H7OH and deionized water. The well-known chemical displacement technique was modified to grow the copper particles of specific sizes. SEM and XRD analysis revealed that the outer surface of the porous silicon was covered with copper particles of the crystal orientation inherited from the planes of porous silicon skeleton. The copper crystals were found to have the cubic face centering elementary cell. In addition, the traces of Cu2O cubic primitive crystalline phases were identified. The dimensions of Cu particles were determined by the Feret's analysis of the SEM images. The sizes of the particles varied widely from a few to hundreds of nanometers. A phenomenological model of copper deposition was proposed.

Formation Regularities of Sers-Active Substrates Based on Silver-Coated Mesoporous Silicon

“…The coalescence demonstrates reinforcement of Ag atoms mutual attraction simultaneously to the increase of Ag deposit which is typical for the Volmer-Weber mechanism. The disconnection of Ag agglomerates at the coalescence process allowed reopening the PS surface for new Ag NPs to grow a b c that is in correspondence with the model of metals immersion deposition on PS [6]. Summarizing, the regularity of the Ag deposition consists in the alternation of the formation of the following deposits: the layer of the individual particles (Fig.…”

Nanostructures formed by displacement of porous silicon with copper: from nanoparticles to porous membranes

“…It was found that all copper deposits had a polycrystalline nature with prevalent growth of (111)-oriented crystals. Here, we analyzed the XRD patterns (presented in [24]) and, following Scherrer's formula, calculated that Cu particles consist of 2-nm nanocrystals. That is in good agreement with the known data of EBSD analysis [25].…”

“…Some previous works have shown that copper deposits by displacement on the surface of PS in the form of crystalline NPs [23]. The pore channels limit the size of NPs, while on the outer PS surface, copper particles can be an order of magnitude greater [24]. In fact, the final material of copper displacement deposition on PS represents the layer of the Cu/PS nanocomposite covered with quasi-continuous copper film.…”

“…The initial stages of deposition are accompanied by the formation of copper particles of 2-nm diameter inheriting the crystallographic orientation of the PS skeleton [25]. Further copper particles growth leads to the (111) prevalence orientation of the copper deposit [24,26]. In [24], the outer surface of PS of 55% porosity has been used as a template for the growth of copper particles of controllable sizes.…”

“…Further copper particles growth leads to the (111) prevalence orientation of the copper deposit [24,26]. In [24], the outer surface of PS of 55% porosity has been used as a template for the growth of copper particles of controllable sizes. However, the authors have been faced with the fact that copper deposits according to the island growth mechanism of thin films (like in the case of bulk Si).…”