Control of Composition and Conduction Type of CdTe Film Electrodeposited from Ammonia Alkaline Aqueous Solutions
Control of Composition and Conduction Type of CdTe Film Electrodeposited from Ammonia Alkaline Aqueous Solutions
复制标题
氨碱性水溶液电沉积CdTe薄膜成分和导电类型的控制
DOI：
10.1149/1.1392661
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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;S. Mori;T. Hirato;Y. Awakura
在氨碱性电解液中，Cd(II)-和Te(IV)-分别溶解形成Cd(NH{sub 3}){sub 4}{sup 2+}和TeO{sub 3}{sup 2{minus}}离子，研究了CdTe薄膜的恒电位阴极电沉积。通过改变镀液的pH值（pH 10.5—12.2）和Cd(II)/Te（IV）浓度比，可以控制富Te非晶膜、富Te多晶CdTe膜和富Cd多晶CdTe膜的沉积。与标准氢电极（SHE）相比，在{负}0.70 V下沉积的膜具有平坦光滑的形貌。随着Cd含量的增加，沉积电流密度和效率降低。用Cd-Te-NH{sub 3}-H{sub 2}O体系的电位- ph图解释了沉积行为。根据实验结果，推测CdTe电沉积的机理为：(1)碲原子沉积，(2)镉离子在碲原子表面立即吸附，(3)镉在Te表面欠电位沉积。热处理后富te和富cd的CdTe膜的导电类型分别为p型和n型，而未处理的CdTe膜为n型。
Potentiostatic cathodic electrodeposition of CdTe films was studied using aqueous ammonia-alkaline electrolytic baths in which Cd(II)- and Te(IV)-species were dissolving to form Cd(NH{sub 3}){sub 4}{sup 2+} and TeO{sub 3}{sup 2{minus}} ions, respectively. Deposition of three kinds of films, i.e., Te-rich amorphous, Te-rich polycrystalline CdTe, and Cd-rich polycrystalline CdTe films, can be controlled by changing the pH (pH 10.5--12.2) and Cd(II)/Te(IV) concentration ratio of the baths. All the films deposited at {minus}0.70 V vs. the standard hydrogen electrode (SHE) had a flat and smooth morphology. Deposition current density and efficiency were reduced with increasing Cd content of the film. The deposition behavior was interpreted with a potential-pH diagram of the Cd-Te-NH{sub 3}-H{sub 2}O system. Based on the results, the mechanism of the CdTe electrodeposition was presumed to be (1) deposition of tellurium atoms followed by (2) an immediate adsorption of Cd(II) ions on the surface tellurium atoms, and (3) an underpotential deposition of Cd on the surface Te. Conduction types of the Te-rich and Cd-rich CdTe films after heat-treatment were p- and n-type, respectively, whereas untreated CdTe film was n-type.