Highly Scalable, Atomically Thin WSe2 Grown via Metal-Organic Chemical Vapor Deposition
Highly Scalable, Atomically Thin WSe2 Grown via Metal-Organic Chemical Vapor Deposition
复制标题
DOI：
10.1021/nn5073286
复制
发表时间：
2015-02-01
期刊：
影响因子：
17.1
通讯作者：
Robinson, Joshua A.
中科院分区：
文献类型：
--
作者：
Eichfeld, Sarah M.;Hossain, Lorraine;Robinson, Joshua A.
二硒化钨（WSe 2）是一种二维材料，由于其单层形式的1.65 eV的直接带隙和优异的传输特性，其对于下一代电子和光电器件是令人感兴趣的。然而，如果没有可扩展的合成过程，基于这种2D材料的技术就无法实现。在这里，我们展示了通过金属有机化学气相沉积使用六羰基钨（W（CO）（6））和二甲基硒（（CH 3）（2）Se）的第一个可扩展的大面积，单层和少层WSe 2的合成。除了固有的可扩展性之外，该技术还允许精确控制气相化学，这是使用更传统的氧化物蒸发路线无法获得的。我们发现，温度，压力，Se：W比，和衬底的选择有很大的影响，随后的原子层结构，优化条件产生>8 μ m大小的域。拉曼光谱、原子力显微镜（AFM）和横截面透射电子显微镜（TEM）证实了结晶单层到多层WSe 2是可实现的。最后，TEM和垂直电流/电压传输提供的证据表明，一个原始的货车范德华间隙存在于WSe 2/石墨烯异质结构。
Tungsten diselenide (WSe2) is a two-dimensional material that is of interest for next-generation electronic and optoelectronic devices due to its direct bandgap of 1.65 eV in the monolayer form and excellent transport properties. However, technologies based on this 2D material cannot be realized without a scalable synthesis process. Here, we demonstrate the first scalable synthesis of large-area, mono and few-layer WSe2 via metalorganic chemical vapor deposition using tungsten hexacarbonyl (W(CO)(6)) and dimethylselenium ((CH3)(2)Se). In addition to being intrinsically scalable, this technique allows for the precise control of the vapor-phase chemistry, which is unobtainable using more traditional oxide vaporization routes. We show that temperature, pressure, Se:W ratio, and substrate choice have a strong impact on the ensuing atomic layer structure, with optimized conditions yielding >8 mu m size domains. Raman spectroscopy, atomic force microscopy (AFM), and cross-sectional transmission electron microscopy (TEM) confirm crystalline monoto-multilayer WSe2 is achievable. Finally, TEM and vertical current/voltage transport provide evidence that a pristine van der Waals gap exists in WSe2/graphene heterostructures.