An insitu scanning tunneling microscopy study of Ag electrodeposition on Au(111)

Abstract

In situ scanning tunneling microscopy (STM) was used to study the electrodeposition of silver on Au(111) electrodes from sulfuric acid solution. The process was followed in both the underpotential and overpotential regions. STM images of underpotentially deposited silver revealed a series of ordered adlayer structures of increasing coverage with decreasing potential, namely (√3×√3)R30°, a distorted hexagonal stripe pattern, a (3×3) and, finally, a close-packed (1×1) layer. The bulk deposition was also monitored as a function of the electrode potential. At low overpotentials, a layer-by-layer growth up to at least 10 monolayers was detected. Additionally, a 3D cluster growth took place at the step edges. Finally, deposition of a thick silver layer resulted in the leveling of substrate defects and a very flat surface was obtained.