Monolayer-Directed Electrodeposition of Oxide Thin Films: Surface Morphology versus Chemical Modification

Abstract

In this paper we describe the general role that surface morphology and chemical nature play in guiding the cathodic deposition of oxide thin films onto electrode surfaces. By use of a “featureless” stamp for microcontact printing (μCP), the pregrooved microfeatures (“mountains” and “valleys” representing the track trails) of recordable compact disc (CD-R) gold substrates can be selectively modified with OH- or CH3-terminated self-assembled monolayers (SAMs). For comparison, “flat” gold substrates were patterned with the above SAMs in parallel “microstrips” that are analogous to the CD-R substrate (but no height differences). Electrochemical deposition of zirconia thin films showed that, on the CD-R substrates, surface morphology (height difference) dominates over the blocking effects of the SAMs; that is, deposition occurred primarily on the mountains despite these sites being modified with organic monolayers. For flat gold substrates it was found that n-alkanethiolate SAMs block deposition in modified ar...