Preliminary Studies of GaAs Deposition on Au(100), (110), and (111) Surfaces byElectrochemical Atomic Layer Epitaxy

摘要

The development of a new method for epitaxial growth of compound semiconductorsis briefly described: electrochemical atomic layer epitaxy (ECALE). ECALE is based on the successive underpotential deposition (UPD) of atomic layers of different elements to form a compound. Preliminary studies of the ECALE deposition of GaAs were performed in a thin-layer electrochemical cell with a polycrystalline Au electrode. Potentials required for oxidative UPD of As and reductive UPD of Ga were evaluated with different solution concentrations and pH's. Subsequent studies were performed in an ultrahigh vacuum surface analysis instrument interfaced to an electrochemical cell. A gold single crystal supporting the three low-index planes was used in these studies. Auger electron spectroscopy (AES) and coulometry were used for surface composition analysis, while low energy electron diffraction (LEED) was used for structural analysis. UPD of Ga on As-covered surfaces (Au(100)(2X2)-As and A(110)c(2X2)-As) resulted in stoichiometric coverages on Ga and As on both. Structures displaying (2X2) and c(2X2) LEED patterns were formed on the (100) and (110) faces, respectively. The stability of GaAs in aqueous solutions was evaluated. Potentials vs. pH plots were calculated. GaAs, Electrodeposition, Au Single Crystals, Epitaxy, ALE.