Electrochemical pore formation mechanism in III–V crystals (Part II)

Abstract

Chemical and electrical processes developing at the semiconductor-electrolyte interface under conditions of anodic polarization were analyzed. It was shown that dense chemisorption coatings are formed on the surface of III–V crystals at voltages of pore formation onset, and a degenerate inversion layer is formed on the semiconductor side. In this case, a drop of the largest part of the applied voltage in the adsorption layer creates the prerequisites for nucleophilic substitution reactions involving chemisorbed anions and coordination-saturated atoms under the crystal surface. The mechanisms of these reactions were considered as applied to sphalerite-structured crystals. The results of experimental studies of the structures and compositions of porous layers in III–V crystals formed in various electrolytes at various polarization voltages are explained on the basis of the obtained concepts.