Growth model of van der Waals epitaxy of films: a case of AlN films on multilayer graphene/SiC
Growth model of van der Waals epitaxy of films: a case of AlN films on multilayer graphene/SiC
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薄膜范德华外延生长模型：多层石墨烯/SiC 上 AlN 薄膜的案例
DOI：
10.1021/acsami.7b14494
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发表时间：
2017
影响因子：
9.5
通讯作者：
Xu Ke
中科院分区：
文献类型：
--
作者：
Xu Yu;Cao Bing;Li Zongyao;Cai Demin;Zhang Yumin;Ren Guoqiang;Wang Jianfeng;Shi Lin;Wang Chinhua;Xu Ke
“Volmer-Weber”岛形核和阶梯流生长模型是传统薄膜外延的经典过程。然而，薄膜的货车范德华外延（vdWE）的生长模型仍然没有很好的文献记载。在此，我们给出了在1 - 100 °C的高温下通过氢化物气相外延在多层石墨烯（MLG）/SiC上的AlN膜的vdWE的示例，并揭示了AlN、MLG和SiC的取向关系为（0001）[1-100]AlN||（0001）[1-100]MLG||（0001）[11-20]SiC，这表明vdWE异质界面不是通常的共价键，并且在生长过程中由于无公度的面内晶格而没有过度的应变。值得注意的是，锯齿形裂纹形成后，薄膜冷却到室温，由于应变的各向异性，表明生长模型的vdWE是不同于传统的外延。它是一种逐层外延，没有错切角的平面衬底对于获得单晶薄膜至关重要。此外，该膜可以通过直接机械剥离而无需任何应力层转移到异质衬底上。紫外光传感器装置说明III族氮化物异质集成应用的实例。我们的工作表明了一个很好的一步，为未来的可转移异质集成应用程序的二维材料上的各种化合物薄膜的vdWE。
“Volmer–Weber” island nucleation and step-flow growth model are the classical processes of the conventional epitaxy of films. However, a growth model of van der Waals epitaxy (vdWE) of films is still not very well-documented. Here, we present an example of vdWE of AlN films on multilayer graphene (MLG)/SiC by hydride vapor phase epitaxy at a high temperature of 1100 °C and reveal the orientation relationship of AlN, MLG, and SiC as (0001)[1–100]AlN||(0001)[1–100]MLG||(0001)[11–20]SiC, which suggests that the vdWE heterointerface is not an usual covalent bond and no excessive strain during the growth process owing to the incommensurate in-plane lattices. Remarkably, zigzag cracks are formed because of the anisotropy of strain after the films are cooled down to room temperature, indicating that the growth model of vdWE is different from that of conventional epitaxy. It is a layer-by-layer epitaxy, and a planar substrate without a miscut angle is essential for obtaining single-crystalline films. Additionally, the films can be transferred to foreign substrates by direct mechanical exfoliation without any stressor layer. An ultraviolet photosensor device illustrates an example of III-nitride heterogeneous integration application. Our work demonstrates an excellent step toward the vdWE of varieties of compound films on 2D materials for the applications of transferrable heterogeneous integration in future.