Remote epitaxy through graphene enables two-dimensional material-based layer transfer
Remote epitaxy through graphene enables two-dimensional material-based layer transfer
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DOI：
10.1038/nature22053
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发表时间：
2017-04-20
期刊：
影响因子：
64.8
通讯作者：
Kim, Jeehwan
中科院分区：
文献类型：
--
作者：
Kim, Yunjo;Cruz, Samuel S.;Kim, Jeehwan
外延-在衬底上生长晶体材料-对于半导体工业至关重要，但通常受到两种材料系统之间晶格匹配的限制。这种严格的要求对于货车德瓦尔斯外延（1-10）是宽松的，其中层状或二维（2D）材料上的外延由弱货车德瓦尔斯相互作用介导，并且还允许从2D表面容易地释放层（3，8）。已经认为2D材料是用于货车德瓦尔斯外延的唯一种子层（3-10）。然而，2D材料下方的衬底仍然可能与外延期间生长的层（外延层）相互作用，如在石墨烯（11-13）记录的所谓润湿透明度的情况下。在这里，我们表明，石墨烯的弱货车德瓦尔斯势不能完全屏蔽许多衬底的更强的势场，这使得外延生长发生，尽管它的存在。我们使用密度泛函理论计算，以建立吸附原子将经历远程外延注册表与基板通过基板外延层间隙高达9埃，这个间隙可以容纳单层石墨烯。我们通过单层石墨烯在GaAs（001）衬底上同质外延生长GaAs（001）证实了预测，并表明该方法也适用于InP和GaP。生长的单晶膜从石墨烯涂覆的基底快速释放，并且当并入发光器件中时表现得与常规制备的膜一样好。该技术使得任何类型的半导体膜能够通过2D材料从底层衬底复制，然后将所得的外延层快速释放并转移到感兴趣的衬底上。该方法在非硅电子和光子学的背景下特别有吸引力，其中重新使用石墨烯涂覆的衬底（8）的能力允许节省非硅衬底的高成本。
Epitaxy-the growth of a crystalline material on a substrate-is crucial for the semiconductor industry, but is often limited by the need for lattice matching between the two material systems. This strict requirement is relaxed for van der Waals epitaxy(1-10), in which epitaxy on layered or two-dimensional (2D) materials is mediated by weak van der Waals interactions, and which also allows facile layer release from 2D surfaces(3,8). It has been thought that 2D materials are the only seed layers for van der Waals epitaxy(3-10). However, the substrates below 2D materials may still interact with the layers grown during epitaxy (epilayers), as in the case of the so-called wetting transparency documented for graphene(11-13). Here we show that the weak van der Waals potential of graphene cannot completely screen the stronger potential field of many substrates, which enables epitaxial growth to occur despite its presence. We use density functional theory calculations to establish that adatoms will experience remote epitaxial registry with a substrate through a substrate-epilayer gap of up to nine angstroms; this gap can accommodate a monolayer of graphene. We confirm the predictions with homoepitaxial growth of GaAs(001) on GaAs(001) substrates through monolayer graphene, and show that the approach is also applicable to InP and GaP. The grown single-crystalline films are rapidly released from the graphene-coated substrate and perform as well as conventionally prepared films when incorporated in light-emitting devices. This technique enables any type of semiconductor film to be copied from underlying substrates through 2D materials, and then the resultant epilayer to be rapidly released and transferred to a substrate of interest. This process is particularly attractive in the context of non-silicon electronics and photonics, where the ability to re-use the graphene-coated substrates(8) allows savings on the high cost of non-silicon substrates.