Extraordinary Room-Temperature Photoluminescence in Triangular WS2 Monolayers
Extraordinary Room-Temperature Photoluminescence in Triangular WS2 Monolayers
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DOI：
10.1021/nl3026357
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发表时间：
2013-08-01
期刊：
影响因子：
10.8
通讯作者：
Terrones, Mauricio
中科院分区：
文献类型：
--
作者：
Gutierrez, Humberto R.;Perea-Lopez, Nestor;Terrones, Mauricio
单个单层金属二硫族化合物是原子薄的二维晶体，具有不同于它们的块状对偶物的有吸引力的物理性质。在这里，我们描述了直接合成具有三角形形貌和强室温光致发光（PL）的WS2单层。拉曼响应以及发光作为S-W-S层数的函数也被报道。由于从单层的直接带隙到多层的间接带隙的转变，PL随着层数的增加而减弱。WS2单分子层的边缘显示出异常强烈的PL信号，大约是血小板中心的25倍。血小板边缘的结构和化学成分似乎对PL增强至关重要。
Individual monolayers of metal dichalcogenides are atomically thin two-dimensional crystals with attractive physical properties different from those of their bulk counterparts. Here we describe the direct synthesis of WS2 monolayers with triangular morphologies and strong room-temperature photoluminescence (PL). The Raman response as well as the luminescence as a function of the number of S-W-S layers is also reported. The PL weakens with increasing number of layers due to a transition from direct band gap in a monolayer to indirect gap in multilayers. The edges of WS2 monolayers exhibit PL signals with extraordinary intensity, around 25 times stronger than that at the platelet's center. The structure and chemical composition of the platelet edges appear to be critical for PL enhancement.