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Chemical Bath Deposition of Copper Sulfide on Functionalized SAMs: An Unusual Selectivity Mechanism
journal contribution
posted on 2020-03-19, 13:04 authored by Jenny
K. Hedlund, Tania G. Estrada, Amy V. WalkerWe
have investigated the chemical bath deposition (CBD) of CuS
using thioacetamide on functionalized self-assembled monolayers (SAMs)
using scanning electron and optical microscopies, X-ray photoelectron
spectroscopy, and time-of-flight secondary ion mass spectrometry.
For all SAMs studied, the amount of CuS deposited is strongly dependent
on the bath pH and can be attributed to the interaction of the SAM
terminal groups with the chalcogenide ions present in solution. For
−CH3-terminated SAMs, there is a steady increase
in the amount of CuS deposited with an increase in the bath pH because
there is an increase in the concentration of chalcogenide ion. However,
for −OH- and −COOH-terminated SAMs, we observe that
the maximum amount of CuS is deposited at pH 10. We attribute this
behavior to a competition between the repulsion of the chalcogenide
ions by the negatively charged SAM terminal groups and an increase
in the chalcogenide ion concentration with an increase in the bath
pH. Using the interaction of the chalcogenide ions with the different
SAM terminal functional groups, we demonstrate that CuS can be selectively
deposited on the −CH3-terminated areas of patterned
−OH/–CH3- and −COOH/–CH3-terminated SAMs.