ON THE ANODIC FILM FORMATION OF HGS

The kinetics of the anodic film formation of HgS was investigated by analysing current i-time t transients. The film formation proceeds via successive deposition of two-dimensional monolayers and three-dimensional islands. The deposition of the first monolayer was theoretically described by a mechanism where adsorption-desorption is a step parallel to nucleation and growth. The second monolayer arises from instantaneous nucleation and growth of constant rate whereas the third layer develops by hemispherical nucleation and diffusion-controlled growth. The change of two- to three-dimensional film formation was interpreted in terms of the Stranski-Krastanov mechanism.