Coverage Dependent Structure of Electrochemically Deposited Cu on p-GaAs(100) in H2SO4 Solution Determined by In Situ Surface X-Ray Absorption Fine Structure Spectra

In situ surface X-ray absorption fine structure technique was applied to study the structures of electrochemically deposited Cu on a p-GaAs(100) electrode with various coverage. Extended X-ray absorption fine structure (EXAFS) spectra of Cu were obtained with high S/N ratio even from submonolayer deposit. EXAFS data showed that the Cu clusters were formed on the p-GaAs(100) electrode as the deposition exceeded more than one monolayer. The structure of the submonolayer deposit was different from that of the bulk deposit. The neighboring atoms in the latter are only Cu of the fcc structure but those in the former are O and Cu of shorter bond length.