Self-terminating Growth of Pt by Electrochemical Deposition
Yihua Y. Liu, Dincer Gokcen, Ugo Bertocci, Thomas P. Moffat
A self-terminating rapid electrodeposition process for controlled growth of Pt monolayer films from a K_(2)PtCl_(4)-NaCl electrolyte has been developed that is tantamount to wet atomic layer deposition (ALD). Despite the deposition overpotential being in excess of 1 V, Pt deposition is quenched at potentials just negative of proton reduction by an alteration of the double layer structure induced by a saturated surface coverage of underpotential deposited hydrogen, (H_(upd)). The surface is reactivated for Pt deposition by stepping the potential to more positive values where Hupd is oxidized and fresh sites for adsorption of PtCl_(4)^(2-) become available. Periodic pulsing of the potential enables sequential deposition of two dimensional (2-D) Pt layers to fabricate films of desired thickness relevant to a range of advanced technologies.