Potential‐pH Diagram of the Cd ‐ Te ‐ NH 3 ‐ H 2 O System and Electrodeposition Behavior of CdTe from Ammoniacal Alkaline Baths
Potential‐pH Diagram of the Cd ‐ Te ‐ NH 3 ‐ H 2 O System and Electrodeposition Behavior of CdTe from Ammoniacal Alkaline Baths
复制标题
Cd-Te-NH3-H2O 体系的电位-pH 图和氨碱浴中 CdTe 的电沉积行为
DOI：
10.1149/1.1391846
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发表时间：
1999
影响因子：
3.9
通讯作者：
Y. Awakura
中科院分区：
文献类型：
--
作者：
K. Murase;Hiroto Watanabe;T. Hirato;Y. Awakura
基于两个系统的图，构建了系统的电位- pH图，并讨论了pH值为10.7的氨碱性CdTe电解液的氧化还原行为。CdTe在酸性和碱性区域具有广泛的稳定域，并且用图很好地解释了氧化还原行为。该图表明，CdTe的阴极电沉积发生在碲金属的稳定域内，即在pH < 11.5的电浴中，CdTe的电位低于体Te的沉积电位，高于体Cd的沉积电位，而在较高的pH区域，CdTe预计直接从Te（IV）和Cd（II）离子沉积。沉积机理考虑如下：(i)碲层沉积，随后（ii）镉在其上立即欠电位沉积，从而阻止了碲的大量沉积。可以认为，化学计量CdTe更容易在碱性浴中电沉积，因为与常规使用的pH为0-2的酸性区相比，碱性区中金属碲的区域更窄。因此，单质碲的大块沉积不太可能发生在碱性浴中。©1999电化学学会。版权所有。
A potential‐pH diagram of the system was constructed based on diagrams of the and systems and discussed in connection with the redox behavior of an ammonia‐alkaline CdTe electrolytic bath with pH 10.7. CdTe has a wide domain of stability throughout the acidic and alkaline regions, and the redox behavior was well explained with the diagram. The diagram indicated that the cathodic electrodeposition of CdTe occurs across a domain of stability of tellurium metal, i.e., at lower potentials than the deposition potential of bulk Te and higher than that of bulk Cd, with respect to the bath with pH < ca. 11.5, while in the higher pH region, CdTe is expected to deposit directly from Te(IV) and Cd(II) ions. The deposition mechanism is considered as follows: (i) deposition of tellurium layer followed by (ii) an immediate underpotential deposition of Cd on it, which prevents the bulk deposition of tellurium. It can be considered that the stoichiometric CdTe is more easily electrodeposited from alkaline baths, since the domain for tellurium metal is narrower in the alkaline region compared to the conventionally employed acidic region with pH 0–2. Therefore, the bulk deposition of elemental tellurium is less apt to occur from an alkaline bath. © 1999 The Electrochemical Society. All rights reserved.