电沉积Bi2Te3基薄膜的电化学阻抗谱研究

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.

Electrochemical Impedance Spectroscopic Study of Electrodeposited Bi_2Te_3-based Thin Films

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.