Regensburg 2004 – wissenschaftliches Programm
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O: Oberflächenphysik
O 14: Postersitzung (Adsorption an Oberflächen, Epitaxie und Wachstum, Organische Dünnschichten, Oxide und Isolatoren, Phasenübergänge, Rastersondentechniken, Struktur und Dynamik reiner Oberflächen)
O 14.32: Poster
Montag, 8. März 2004, 18:00–21:00, Bereich C
Electrochemical synthesis of CdS-Films on Cu(111) — •S. Hümann, A. Spänig, P. Broekmann, and K. Wandelt — Institut für Physikalische Chemie; Wegelerstr.12; 53115 Bonn
Electrochemical Atomic Layer Epitaxy (ECALE) has been found to be a useful method to grow thin layers of semiconductor compounds at solid/liquid interfaces. In this contribution we present STM data dealing with the epitaxial growth of ultrathin CdS-films on a Cu(111) electrode surface.
It will be shown that the atomic structure and the morphology of the resulting 2 layers thick CdS film strongly depend on the first layer adsorbed on the copper substrate.
We present CdS-films prepared by starting up with a sulfide covered copper surface as a template. Depending on the applied electrode potential two different sulfide layers can be observed by STM, on top of a Cu(111) surface exposed to a 10 mM S2−electrolyte:
1. an incommensurate moiré pattern
2. a commensurate (√7 × √7)R19.1o adlayer
Cd deposition on the (√7 × √7)R19.1o phase at a potential of -375 mV with respect to the RHE results in the formation of a CdS-phase revealing a complex dislocation network which also shows a √7 strukture with respect to the Cu(111)-substrate. Subsequent termination with S2− leads to the loss, of this highly ordered dislocation network.