Formation of oxide crystallites on the porous GaAs surface by electrochemical deposition

Abstract

We demonstrate how the formation of octahedral microcrystals of arsenic oxide As2O3 in the form of arsenolite with a size of 200 nm to 10 μm can be initiated by the electrochemical etching method with simultaneous deposition on the surface of substrates with n-GaAs (111). Crystallites were formed on a previously synthesized porous layer of GaAs. To explain the behavior of formation on the surface of the monocrystalline GaAs porous layer and As2O3 crystallites in the electrochemical reaction, we propose a qualitative model based on the decomposition of binary semiconductors in contact with electrolytes. Under this model, the crystallization of precipitated oxides occurs as a result of the transfer of ions to the crystal surface as a result of the electrolysis process. The formation of the composite structure takes place on the surface of the semiconductor and is characterized by the minimization of elastic energy. XRD analysis showed the formation of a complex compound of As2O3 and As0.172Sb0.570O1.113. The appearance of antimony is explained in terms of the formation of new centers when the As atom is replaced by an Sb doping atom in the crystal. Directed controlled oxidation technologies make it possible to synthesize a reliable passivating layer consisting of one type of oxide, namely As2O3 in the cubic phase of arsenolite. In addition, such structures can be used in photonics devices and as photocatalysts.