Thermochemistry of the E-ALD process for the growth of CuxZnyS on Ag(111): Interpretation of experimental data

Abstract

The electrochemical atomic layer deposition (E-ALD) growth of chalcogenides materials enables the deposition of technologically interesting ultra-thin films. However, this method raises some questions about the actual growth mechanism. We addressed one of the more interesting anomalies reported lately: the occurrence of the Zn-deficiency and of the polycrystalline thread-like overgrown structures in the E-ALD growth of Cu x Zn y S. The present study was developed using a computational speciation approach under the mass balance method. Exploiting a well-established computational approach, but uncommonly applied to the electrochemical science, we calculated the predominance charts and the equilibrium speciation of the solid phases during the electrochemical process. On this basis, we obtained a deep insight into the mechanism underlying the E-ALD process from a thermodynamic standpoint. Thus, we identified the crucial steps of the Cu x Zn y S growth leading to the anomalies object of this research.

Electrochemical Atomic Layer Epitaxy Deposition of Ultrathin SnTe Films

“…Subsequently, the deposited films were crystallized in the preferential directions along the (200) and (222) planes, which suggested an epitaxial growth, as expected with the use of the ECALE technique. Epitaxial growth is highly influenced by the UPD deposition as the UPD process is a surface limited process that allows the monolayer that is being deposited to copy the crystalline structure of the substrate [10,30]. Despite the XPS results in its favor, no peaks for elemental Te or Sn were observed in the XRD pattern, suggesting that the amounts of these elements were below the detection threshold.…”

Underpotential‐Assisted Electrodeposition of Highly Crystalline and Smooth Thin Film of Bismuth

“…Therefore, the UPD method allows to finely control the deposition and permits a crystalline growth by minimizing the quantity of defects. The process typically occurs between metals and non-metals and has been previously used by our research group to synthesize various binary and ternary semiconductors and alloys [39][40][41][42][43] including Bi 2 Se 3 . [44] Starting from the bismuth compound, we took a step further with the selective electrodesorption-based atomic layer deposition (SEBALD): [45,46] in fact, selenium stripping led to an uniform and crystalline thin film of bismuth, [47] that it would otherwise have been difficult to obtain with the direct bulk deposition over the Nernst potential.…”

Enhancing the photocatalytic activity of Cu0.25Zn0.75S nanodisks by metallic Ag loading in the visible-light region

“…5,15,16 A CuS/ ZnS core/shell structure was developed to passivate the trap states of CuS and restrain the photocorrosion, which can efficiently decompose methylene blue and rhodamine B under visible-light irradiation. 4,17,18 CuS-ZnS-based materials such as Cu x Zn y S lms were prepared by pulsed laser deposition, 19 spray pyrolysis, 20 electrochemical deposition and photochemical deposition 12,[21][22][23][24][25] to enhance the visible-light photocatalytic capacity. Besides, Cu-Zn-S-sensitized TiO 2 nanotube arrays (Cu-Zn-S/TiO 2 NTAs) exhibited excellent photocatalytic activity compared with TiO 2 NTAs.…”