New Opportunities in Pulse Plating Via Self-Terminated Electrodeposition Reactions

Tuesday, 30 May 2017: 11:20
Marlborough B (Hilton New Orleans Riverside)
T. P. Moffat (National Institute of Standards and Technology), Y. Liu (LAM Research), S. H. Ahn (National Institute of Standards and Technology), N. L. Ritzert (NIST, National Institute of Standards and Technology), R. Wang (NIST), D. Gokcen (National Institute of Standards and Technology), C. Hangarter (U.S. Naval Research Laboratory), and U. Bertocci (National Institute of Standards and Technology)
Recently, electrodeposition of Pt and Ir was shown to exhibit an unanticipated self-terminating characteristic that enables controlled deposition of monolayer thick films from simple binary electrolytes. Specifically, film growth at negative potentials is quenched by the formation of a saturated layer of adsorbed H, and alteration of the double layer structure, that in combination block adsorption of the metal halide precursor complex. Periodic pulsing of the potential to desorb H enables sequential deposition of additional Pt and Ir layers to fabricate films of desired thickness relevant to a range of advanced technologies. Overall the process is tantamount to a “wet” form of atomic layer deposition (ALD). More recently, self-terminated deposition of the iron group metals, Fe, Co and Ni, was also observed. In contrast to the Pt group metals, growth termination of the iron group metals is attributed to OH- adsorption that is coincident with the onset of water reduction. The application of the above deposition processes to a variety of substrates, e.g. Au, Ni, etc, is underway along with an assessment of the catalytic activity of the resulting electrodes towards water electrolysis and related fuel cell reactions. In this lecture details of the growth process and resulting electrocatalytic performance will be summarized.