ナノ薄膜の創製と熱電的性質の解明および閉じ込め効果の検証

利用分子束外延（MBE）技术制备碱土六硼化物薄膜是一个极具挑战性的课题。在夏季，获得结晶膜的最初困难被克服了，并且相对高结晶度的硼化锶薄膜现在已经成功地制造出来了。在此基础上，构建了自制的气相沉积系统，并以单质锶和十硼烷为前驱体，采用气相沉积法制备了六硼化锶薄膜。我们对薄膜的结构和结晶度进行了详细的研究，发现使用CVD工艺可以非常快速地沉积高结晶的SrB6。我们还测量了薄膜的热电性能，发现它们与报道的体积值相似，除了出乎意料的高电阻率。研究结果表明，单质金属源与十硼烷结合是制备高结晶硼化物薄膜的有效途径，对今后金属硼化物薄膜的研究具有重要意义。对沉积过程和热电性能测量的描述也为热电材料薄膜纳米结构的制造开辟了道路。令人惊讶的是，薄膜也实现了快速生长（“低压CVD法沉积热电六硼化锶薄膜”晶体生长杂志，小修订）。

The very challenging topic of fabricating thin films of alkaline earth hexaborides using the molecular beam epitaxy (MBE) technique was carried out. Initial difficulties with achieving crystalline films were overcome during the summer, and strontium boride thin films of relatively high crystallinity have now been successfully fabricated.In addition to this, a home-made CVD was constructed, and the successful growth of strontium hexaboride thin films by a CVD process using elemental strontium and decaborane as the precursors, was achieved. We have performed a detailed study of the structure and crystallinity of the films and found that highly crystalline SrB6 can be deposited remarkably fast using the described CVD process. We also measured the thermoelectric properties of the films and found them to be similar to reported bulk values apart from an unexpectedly high electrical resistivity. The work is significant because it shows that using elemental metal sources together with decaborane can be an effective way to deposit highly crystalline boride thin films, which should be useful in future studies of metal boride thin films. The description of the deposition process and measurement of thermoelectric properties also opens the way for efforts to fabricate thin film based nanostructures for thermoelectrics. Surprisingly fast film growth was also achieved (“Deposition of Thermoelectric Strontium Hexaboride Thin Films by a Low Pressure CVD Method" Journal of Crystal Growth, in minor revision).