Underpotential deposition is an electrochemical process in which a dissimilar metal is electrochemically deposited on a metal surface. The deposition results in the formation of a monolayer or sub-monolayer coverage which can be controlled by the applied potential. Such ease of control of sub-monolayer deposition is clearly of interest in the area of nanotechnology. The deposition of lead monolayers onto a silver surface has been extensively studied both for polycrystalline and single crystal surfaces. The mechanism of deposition in a general sense is understood. Many aspects, however, are still not well understood. Does the initial deposition take place at specific sites on the surface or is it random? Is the deposition site specific and can we identify the sites and characterize them? Once deposition has begun do these sites inhibit new deposition sites forming? When the potential is changed to increase the coverage does the deposition occur at the same sites or do new or different deposition sites develop?

Dr. Larkin.s research seeks to study polycrystalline surfaces and investigate the electrochemical deposition at the atomic level in real time using a Potentiostat/Galvanostat which is interfaced to scanning probe microscope. The preparation of silver surfaces and their characterization is central to this project. This can more easily be undertaken using the Atomic Force Microscope (AFM) rather than the Scanning Tunneling Microscope (STM). The studies of the deposition process will ultimately be performed, however, using the STM.

Participants will have a diverse experience. They will work in three experimental fields: Electrochemistry, Atomic Force/Scanning Tunneling Microscopy and Metallurgy. They will gain insight into the interfacing of two very different instrumental methods to investigate a fundamental electrochemical process. Hands-on experience will be obtained in the preparation of metal surfaces using polishing and annealing techniques

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