Tightly bound trions in monolayer MoS2
Tightly bound trions in monolayer MoS2
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DOI：
10.1038/nmat3505
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发表时间：
2013-03-01
期刊：
影响因子：
41.2
通讯作者：
Shan, Jie
中科院分区：
文献类型：
--
作者：
Mak, Kin Fai;He, Keliang;Shan, Jie
二维（2D）原子晶体，如石墨烯和过渡金属二硫属化物，已成为一类具有显着物理性能的新材料（1）。与石墨烯相反，单层MoS 2是具有直接能隙的非中心对称材料（2，5）。最近在这种材料中证明了强的光致发光（2，3），场效应晶体管（6）中电流开/关比超过10（8），以及通过光学螺旋性（7-9）的有效谷和自旋控制。在这里，我们报告的光谱识别在单层二硫化钼场效应晶体管的紧密结合的负trions，准粒子组成的两个电子和一个洞。这些准粒子可以用谷和自旋极化空穴光学地产生，在传统的半导体中没有类似物。它们还具有很大的结合能（类似于20 meV），即使在室温下也很重要。我们的研究结果开辟了可能性的基础研究多体相互作用和光电和valleytronic应用在二维原子晶体。
Two-dimensional (2D) atomic crystals, such as graphene and transition-metal dichalcogenides, have emerged as a new class of materials with remarkable physical properties(1). In contrast to graphene, monolayer MoS2 is a non-centrosymmetric material with a direct energy gap(2,5). Strong photoluminescence(2,3) a current on/off ratio exceeding 10(8) in field-effect transistors(6), and efficient valley and spin control by optical helicity(7-9) have recently been demonstrated in this material. Here we report the spectroscopic identification in a monolayer MoS2 field-effect transistor of tightly bound negative trions, a quasiparticle composed of two electrons and a hole. These quasiparticles, which can be optically created with valley and spin polarized holes, have no analogue in conventional semiconductors. They also possess a large binding energy (similar to 20 meV), rendering them significant even at room temperature. Our results open up possibilities both for fundamental studies of many-body interactions and for optoelectronic and valleytronic applications in 2D atomic crystals.