Atomically Thin MoS2: A New Direct-Gap Semiconductor
Atomically Thin MoS2: A New Direct-Gap Semiconductor
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DOI：
10.1103/physrevlett.105.136805
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发表时间：
2010-09-24
影响因子：
8.6
通讯作者：
Heinz, Tony F.
中科院分区：
文献类型：
--
作者：
Mak, Kin Fai;Lee, Changgu;Heinz, Tony F.
本文研究了N = 1，2，…，用光谱法研究了6种S-Mo-S单分子膜。通过吸收、光致发光和光电导光谱的表征，我们追踪了量子限制对材料电子结构的影响。随着厚度的减小，间接带隙，这是低于直接间隙的散装材料，向上移动的能量超过0.6 eV。这导致在单个单层的限制下交叉到直接带隙材料。与块状材料不同，MoS 2单层强烈发光。与块体材料相比，独立单层表现出发光量子效率增加超过10（4）倍。
The electronic properties of ultrathin crystals of molybdenum disulfide consisting of N = 1, 2, ..., 6 S-Mo-S monolayers have been investigated by optical spectroscopy. Through characterization by absorption, photoluminescence, and photoconductivity spectroscopy, we trace the effect of quantum confinement on the material's electronic structure. With decreasing thickness, the indirect band gap, which lies below the direct gap in the bulk material, shifts upwards in energy by more than 0.6 eV. This leads to a crossover to a direct-gap material in the limit of the single monolayer. Unlike the bulk material, the MoS2 monolayer emits light strongly. The freestanding monolayer exhibits an increase in luminescence quantum efficiency by more than a factor of 10(4) compared with the bulk material.