Yang Jun, Mukherjee Samik, Lehmann Sebastian, Krahl Fabian, Wang Xiaoyu, Potapov Pavel, Lubk Axel, Ritschel Tobias, Geck Jochen, Nielsch Kornelius
Institute for Metallic Materials, Leibniz Institute for Solid State and Materials Research, 01069, Dresden, Germany.
Institute of Materials Science, Technische Universität Dresden, 01062, Dresden, Germany.
Small. 2024 Mar;20(10):e2306350. doi: 10.1002/smll.202306350. Epub 2023 Oct 25.
Nanoscale superlattice (SL) structures have proven to be effective in enhancing the thermoelectric (TE) properties of thin films. Herein, the main phase of antimony telluride (Sb Te ) thin film with sub-nanometer layers of antimony oxide (SbO ) is synthesized via atomic layer deposition (ALD) at a low temperature of 80 °C. The SL structure is tailored by varying the cycle numbers of Sb Te and SbO . A remarkable power factor of 520.8 µW m K is attained at room temperature when the cycle ratio of SbO and Sb Te is set at 1:1000 (i.e., SO:ST = 1:1000), corresponding to the highest electrical conductivity of 339.8 S cm . The results indicate that at the largest thickness, corresponding to ten ALD cycles, the SbOx layers act as a potential barrier that filters out the low-energy charge carriers from contributing to the overall electrical conductivity. In addition to enhancing the scattering of the mid-to-long-wavelength at the SbO /Sb Te interface, the presence of the SbO sub-layer induces the confinement effect and strain forces in the Sb Te thin film, thereby effectively enhancing the Seebeck coefficient and reducing the thermal conductivity. These findings provide a new perspective on the design of SL-structured TE materials and devices.
纳米级超晶格（SL）结构已被证明可有效提高薄膜的热电（TE）性能。在此，通过原子层沉积（ALD）在80°C的低温下合成了具有亚纳米层氧化锑（SbO）的碲化锑（SbTe）薄膜的主相。通过改变SbTe和SbO的循环次数来定制SL结构。当SbO和SbTe的循环比设置为1:1000（即SO:ST = 1:1000）时，在室温下可获得520.8 μW m K的显著功率因数，对应最高电导率为339.8 S cm。结果表明，在对应十个ALD循环的最大厚度处，SbOx层充当势垒，过滤掉低能量电荷载流子对整体电导率的贡献。除了增强SbO/SbTe界面处中长波长的散射外，SbO子层的存在还会在SbTe薄膜中引起限制效应和应变力，从而有效提高塞贝克系数并降低热导率。这些发现为SL结构的TE材料和器件的设计提供了新的视角。
