Synthesis and Thermal Instability of High-Quality Bi2Te3/Sb2Te3 Superlattice Thin Film Thermoelectrics

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• 作者：Anna-Lena Hansen ; Torben Dankwort ; Markus Winkler ; Jeffrey Ditto ; Dave C. Johnson ; Jan D. Koenig ; Kilian Bartholom茅 ; Lorenz Kienle ; Wolfgang Bensch
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：November 25, 2014
• 年：2014
• 卷：26
• 期：22
• 页码：6518-6522
• 全文大小：378K
• ISSN：1520-5002

文摘

The quality and temperature stability of 1 nm Bi₂Te₃/5 nm Sb₂Te₃ superlattices prepared by molecular beam epitaxy for the first time was investigated by in situ and ex situ X-ray diffraction and transmission electron microscopy. Upon heating, the superlattice structures are not stable against interdiffusion of the components, with micro- and nanostructural changes occurring at temperatures as low as 200 掳C. The interdiffusion preferably starts next to superlattice defects. At 300 掳C the Bi₂Te₃ and Sb₂Te₃ layers were mostly interdiffused, forming the thermodynamically stable Sb_1.66Bi_0.33Te₃ alloy. The data suggests that structural integrity of Bi₂Te₃/Sb₂Te₃ superlattices will not be stable for extended times above 200 掳C, thus inhibiting application of such superlattices over a wide temperature range.