半导体热电材料Bi1-xSbx薄膜的电化学制备

B I1-XSBX半导体合金是性能优异的热电和磁电功能材料,为制备固态电制冷器件、温差发电器件和磁电器件的重要材料。电化学沉积薄膜技术工艺设备简单成本低,在半导体薄膜制备方面有很好的应用前景。系统研究了高浓度盐酸(2.4 MOL/L)的B I和SB盐酸溶液,成份从纯铋逐步变化到纯锑的B I1-XSBX合金半导体薄膜电化学沉积特性。测试了沉积过程I-V循环曲线和和沉积电荷效率等电化学参数。结果表明在所有成份范围内都可以得到典型的B I1-XSBX固溶体结构的高质量薄膜。薄膜生长为典型的溶液扩散控制过程,具有高的沉积电荷效率。薄膜沉积和溶解之间的电位差随溶液中SB(Ⅲ)离子浓度增加而增大,生长的薄膜越来越稳定。在30%SB浓度附近,电化学过程、薄膜结构和性能发生明显的突变。应用X射线衍射和电子显微镜研究薄膜结构,发现薄膜具有明显的(012)择优取向,薄膜晶粒尺寸也随SB浓度的增加而变化。

Fabrication of Bi1-xSbx Thermoelectric Semiconductor Films by Electrodeposition

Bi_(1-x)Sb_x semiconductor alloy are important thermoelectric and magnetoelectronic materials,exhibiting unusual electronic properties,and are of interest for electric-cooling,thermal energy conversion,and magnetoelectronic devices.Electrochemical deposition is of simple and low cost method,displaying a potential application in the deposition of semiconductor films.The electrodeposition of Bi_(1-x)Sb_x thermoelectric film from Bi and Sb chloride electrolyte with high concentration of chloride acid was investigated systematically.The concentration of Bi_(1-x)Sb_x in solution was gradually changed from pure Bi to pure Sb.The structures of deposited films were investigated with electron microscopy(SEM,TEM),electron probe(WBS),and X ray diffraction method(XRD).The results shown that the high concentration of chloride acid of electrolyte was effective to avoid the tendency of formation of antimony oxide in the electrolyte,and high quality Bi_(1-x)Sb_x films were electrodeposited across the entire composition range from pure Bi to pure Sb.The films present a textured crystal structure,with(012) preferred orientation,and the grain size also changed for different solution composition.The electrodeposition process is controlled by the solution diffusion.The potential gap between the deposition and the strip of the films varied with the change of solution composition,and process of deposition to stripping for antimony film is more unreversible than that for bismuth film.