Ohta Hiromichi, Sugiura Kenji, Koumoto Kunihito
Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan.
Inorg Chem. 2008 Oct 6;47(19):8429-36. doi: 10.1021/ic800644x.
Thermoelectric energy conversion technology to convert waste heat into electricity has received much attention. In addition, metal oxides have recently been considered as thermoelectric power generation materials that can operate at high temperatures on the basis of their potential advantages over heavy metallic alloys in chemical and thermal robustness. We have fabricated high-quality epitaxial films composed of oxide thermoelectric materials that are suitable for clarifying the intrinsic "real" properties. This review focuses on the thermoelectric properties of two representative oxide epitaxial films, p-type Ca 3Co 4O 9 and n-type SrTiO 3, which exhibit the best thermoelectric figures of merit, ZT (= S (2)sigma Tkappa (-1), S = Seebeck coefficient, sigma = electrical conductivity, kappa = thermal conductivity, and T = absolute temperature) among oxide thermoelectric materials reported to date. In addition, we introduce the recently discovered giant S of two-dimensional electrons confined within a unit cell layer thickness ( approximately 0.4 nm) of SrTiO 3.
将废热转化为电能的热电能量转换技术已备受关注。此外，金属氧化物近来被视作热电发电材料，鉴于其在化学和热稳定性方面相较于重金属合金具有潜在优势，因而能够在高温下运行。我们制备了由氧化物热电材料构成的高质量外延薄膜，这类薄膜适用于阐明其本征的“真实”特性。本综述聚焦于两种具有代表性的氧化物外延薄膜的热电特性，即p型Ca₃Co₄O₉和n型SrTiO₃，在迄今报道的氧化物热电材料中，它们展现出了最佳的热电优值ZT（=S²σTκ⁻¹，其中S为塞贝克系数，σ为电导率，κ为热导率，T为绝对温度）。此外，我们还介绍了近期在SrTiO₃的单胞层厚度（约0.4纳米）内发现的二维电子的巨大塞贝克系数。
