Co₂S₃thin layer: unusual electrochemical behaviour during direct Ni electroplating

EQCM study of electrochemical modification of Bi2S3 films in the Zn2+-containing electrolyte

“…In contrast, the Cu prebulk deposition in Cu plating solution does not occur and the junction pyrite/Cu metal forms a significant Schottky barrier [27]. During the direct Ni electroplating on the Co 2 S 3 layer Co 2 S 3 converts into NiS and the sheet resistance of modified layer also decreases markedly [19].…”

“…Contrary to Cu 2Àx S, CoS or Bi 2 S 3 layers, a layer of Co 2 S 3 cannot be electroreduced to metallic Co in the supporting electrolyte, while it is easily reduced in the nickel plating electrolyte [19].…”

“…However, a favorable chemical or electrochemical interaction between the sulfide and metal ions in the plating electrolyte can take place. So, due to this reason, the reduction of metal sulfide has been widely studied in metal plating electrolytes as well as in supporting ones not only on insulating polymers, but also on an electrically conductive substrate (glassy carbon) using cyclic voltammetry (CV) [17][18][19][20][21][22]. The electrochemical behavior of metal sulfides such as Cu 2Àx S [26], CoS [17], FeS 2 [27] and Co 2 S 3 [19] differs in various metal plating electrolytes.…”

“…So, due to this reason, the reduction of metal sulfide has been widely studied in metal plating electrolytes as well as in supporting ones not only on insulating polymers, but also on an electrically conductive substrate (glassy carbon) using cyclic voltammetry (CV) [17][18][19][20][21][22]. The electrochemical behavior of metal sulfides such as Cu 2Àx S [26], CoS [17], FeS 2 [27] and Co 2 S 3 [19] differs in various metal plating electrolytes. In the case of the reduction of FeS 2 in the cobalt plating solution [27] the prebulk deposition (PBD) of one or a few monolayers of Co adatoms before the traditional overpotential or bulk deposition was identified.…”

“…Bismuth sulfide films have also been proposed for direct metallization of dielectrics [13]. Successful direct metallization onto modified insulating polymer surfaces or electrically conductive substrates has been proposed using zinc sulfide [14], cobalt sulfide [15][16][17][18][19][20][21], nickel sulfide [22] and bismuth sulfide [23][24][25] as activators. Most commonly, an appropriate metal sulfide layer is deposited on a non-conductive surface using the successive ionic adsorption and reaction (SILAR) method.…”