电沉积Bi_2Te_3基薄膜的电化学阻抗谱研究

Electrochemical Impedance Spectroscopic Study of Electrodeposited Bi_2Te_3-based Thin Films

以不锈钢为基底,利用电化学沉积方法制备Bi2Te3基薄膜材料,并采用X射线衍射技术、电子探针微观分析等方法对薄膜进行结构和成分表征,通过电化学阻抗谱技术对不锈钢表面Bi2Te3的电化学沉积机理进行了初步探讨.结果表明Bi-Te和Bi-Te-Se体系具有相似的电化学沉积机理,即Bi3+和2HTeO+或H2SeO3首先被还原为Bi单质和Te或Se单质,然后Bi单质与Te或Se单质反应生成Bi2Te3基化合物,而Bi-Sb-Te体系中,2HTeO+首先被还原为Te单质,生成的Te再与Bi3+和Sb(III)反应生成Bi2Te3基化合物,三种体系的沉积都受电化学极化控制.

The Bi2Te3-based thin films have been prepared by electrochemical deposition on stainless-steel substrates.The microstructure and composition of the films were studied by X-ray diffraction（XRD） and electron probe microanalysis（EPMA）.The deposition mechanisms of Bi2Te3 thin films on stainless-steel substrates were preliminary investigated using electrochemical impedance spectroscopy（EIS）.The results showed that the similar deposition mechanisms were obtained for Bi-Te binary and Bi-Te-Se ternary systems,i.e.,the Bi3＋,2 HTeO＋ and H2SeO3 were electrochemically reduced to form simple substances Bi（0）,Te（0） and Se（0）,respectively,then the Bi2Te3-based compounds were formed by reacting Te（0） or Se（0） with Bi（0）.For Bi-Sb-Te ternary system,the 2 HTeO＋ was first electrochemically reduced to form simple substance Te（0）,and then the Bi2Te3-based compounds were formed by reacting Te（0） with Bi3＋ and Sb（III）.The deposition processes were controlled by electrochemical polarization.