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Optimization of the nucleation-site density for the electrodeposition of cadmium sulfide on indium-tin-oxide

Shen, Sheng and Zhang, Xiaoyue and Mubeen, Syed and Soriaga, Manuel P. and Stickney, John L. (2019) Optimization of the nucleation-site density for the electrodeposition of cadmium sulfide on indium-tin-oxide. Electrochimica Acta, 316 . pp. 105-112. ISSN 0013-4686. doi:10.1016/j.electacta.2019.05.120.

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Cadmium sulfide (CdS) is a preferred heterojunction partner for a number of chalcogenide-based solar cells. In view of this, interest has grown in the use of solution-based deposition techniques as an alternative route for the preparation of uniform ultrathin films of CdS. However, the quality of the electrodeposited CdS films on indium-tin oxide (ITO) remains far from optimal. This is because the ITO surface is electrochemically heterogeneous due to the presence of indium oxide; nucleation and further electrodeposition of CdS does not transpire on the oxided sites. Hence, only coarse-grained coatings, instead of homogeneous ultrathin films, are generated at un-pretreated ITO surfaces. In the present study, a mitigation of the amount of interfacial In oxide was attempted in order to increase the nucleation-site (indium-metal site) density. The procedure consisted of two steps: (i) Mild electrochemical reduction of the ITO to convert surface In(III) to In(0), followed by (ii) surface-limited redox replacement (SLRR) of In(0) by Cu via an aqueous solution of Cu^(2+). This procedure resulted in the formation of a high density of oxide-free Cu on which CdS nuclei would form; the thickness was such that optical transparency was largely undiminished. A ten-fold increase in CdS site density was observed, and that permitted the epitaxial growth of a second semiconductor, CdTe, atop the CdS film. The influences of applied potential and deposition time on nucleation-site sizes and densities were also studied.

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Soriaga, Manuel P.0000-0002-0077-6226
Additional Information:© 2019 Published by Elsevier Ltd. Received 5 April 2019, Revised 22 May 2019, Accepted 23 May 2019, Available online 24 May 2019. Support from the National Science Foundation, DMR 1410109, is gratefully acknowledged. Thanks are extended to the Georgia Electron Microscopy for use of their SEM and Dr. Ryan Hilli’s group for their spectrophotometer. The Joint Center for Artificial Photosynthesis at the California Institute of Technology, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy (DE-SC0004993), provided assistance for Professor M. P. Soriaga. We thank Dr. Andrea Resta, Synchrotron Soleil, L’Orme des Merisiers, Gif-sur-Yvette, France for his contributions to this work. Author contributions: The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Funding sources: DMR 1410109.
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
Subject Keywords:Indium-tin-oxide; Nucleation and Growth; E-ALD; Cadmium Sulfide; Semiconductor Thin Films
Record Number:CaltechAUTHORS:20190524-143304992
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Official Citation:Sheng Shen, Xiaoyue Zhang, Syed Mubeen, Manuel P. Soriaga, John L. Stickney, Optimization of the nucleation-site density for the electrodeposition of cadmium sulfide on indium-tin-oxide, Electrochimica Acta, Volume 316, 2019, Pages 105-112, ISSN 0013-4686, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:95797
Deposited By: Tony Diaz
Deposited On:24 May 2019 21:41
Last Modified:16 Nov 2021 17:15

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