Observation of long-lived interlayer excitons in monolayer MoSe2-WSe2 heterostructures
Observation of long-lived interlayer excitons in monolayer MoSe2-WSe2 heterostructures
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DOI：
10.1038/ncomms7242
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发表时间：
2015-02-01
影响因子：
16.6
通讯作者：
Xu, Xiaodong
中科院分区：
文献类型：
--
作者：
Rivera, Pasqual;Schaibley, John R.;Xu, Xiaodong
用二维材料（例如石墨烯、氮化硼和过渡金属二硫属化物）构建的货车范德华束缚异质结构已经在二维极限下引起了对器件物理和技术的广泛兴趣。一种高度令人垂涎的异质结构是具有II型能带排列的不同单层过渡金属二硫属化物的异质结构，其中束缚电子和空穴位于单个单层中，即层间激子。在这里，我们报告的单层MoSe 2-WSe 2异质结构的层间激子的光致发光和光致发光激发光谱的观察。我们发现，它们的能量和发光强度是高度可调的所施加的垂直栅电压。此外，我们测量层间激子的寿命类似于1.8纳秒，一个数量级长于单层中的层内激子。我们的工作演示了层间电极化的光泵浦，这可能会引发层间激子凝聚的进一步探索，以及在二维激光器，发光二极管和光伏器件中的新应用。
Van der Waals bound heterostructures constructed with two-dimensional materials, such as graphene, boron nitride and transition metal dichalcogenides, have sparked wide interest in device physics and technologies at the two-dimensional limit. One highly coveted heterostructure is that of differing monolayer transition metal dichalcogenides with type-II band alignment, with bound electrons and holes localized in individual monolayers, that is, interlayer excitons. Here, we report the observation of interlayer excitons in monolayer MoSe2-WSe2 heterostructures by photoluminescence and photoluminescence excitation spectroscopy. We find that their energy and luminescence intensity are highly tunable by an applied vertical gate voltage. Moreover, we measure an interlayer exciton lifetime of similar to 1.8 ns, an order of magnitude longer than intralayer excitons in monolayers. Our work demonstrates optical pumping of interlayer electric polarization, which may provoke further exploration of interlayer exciton condensation, as well as new applications in two-dimensional lasers, light-emitting diodes and photovoltaic devices.