Two-dimensional (2D) van der Waals heterostructures (vdWHs) received intensive interest due to their amazing physical properties and broad applications in fields such as ultrasensitive sensors, transistors, and solar cells. Although remarkable progresses were achieved for the synthesis of 2D vdWHs, great challenges still remain for the easy preparation of 2D vdWHs because of the weak interlayer coupling. As a type of 2D semiconductor, the 2D SnSe film is particularly appealing for optoelectronic and thermoelectric devices because of its high thermoelectric and optoelectronic performance. However, the easy preparation of large-area and high-quality 2D SnSe films remains a great challenge. In this work, we proposed an approach to regulate the preparation of high-quality 2D vdWHs, which employed the polarization field of substrate as a key factor to control the diffusion barriers of the adsorbed Sn and Se atoms. Hexagonally stacking α-In2Se3 was selected as such polarized substrate because this substrate exhibits out-of-plane ferroelectricity with upward or downward polarized states at room temperature, and the two degenerated polarized states can be easily switched by applying an external electric field. It was revealed that the polarization field of α-In2Se3 can substantially influence the diffusion behavior of Sn and Se atoms on polarized α-In2Se3 substrate. So, the film growth property of SnSe film is sensitive to the polarization direction of In2Se3 substrate. Our research provides an ideal method to explore the possibility of building 2D functional nanoelectronic devices.

中文翻译：

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本征面外铁电诱导 In2Se3 上 SnSe 薄膜的二维外延

二维（2D）范德华异质结构（vdWH）因其惊人的物理特性以及在超灵敏传感器、晶体管和太阳能电池等领域的广泛应用而受到了广泛的关注。尽管2D vdWHs的合成取得了显着的进展，但由于层间耦合较弱，2D vdWHs的轻松制备仍然存在巨大挑战。作为一种二维半导体，二维 SnSe 薄膜因其高热电和光电性能而对光电和热电器件特别有吸引力。然而，轻松制备大面积、高质量的二维 SnSe 薄膜仍然是一个巨大的挑战。在这项工作中，我们提出了一种调控高质量2D vdWHs制备的方法，该方法利用基底的极化场作为控制吸附的Sn和Se原子的扩散势垒的关键因素。选择六方堆叠的α-In2Se3作为这种极化衬底，因为该衬底在室温下表现出具有向上或向下极化态的面外铁电性，并且可以通过施加外部电场轻松地切换两种简并极化态。结果表明，α-In2Se3 的极化场可以显着影响 Sn 和 Se 原子在极化 α-In2Se3 衬底上的扩散行为。因此，SnSe薄膜的薄膜生长特性对In2Se3衬底的偏振方向敏感。我们的研究为探索构建二维功能纳米电子器件的可能性提供了一种理想的方法。