Optical generation of high carrier densities in 2D semiconductor heterobilayers
Optical generation of high carrier densities in 2D semiconductor heterobilayers
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DOI：
10.1126/sciadv.aax0145
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发表时间：
2019-09
期刊：
影响因子：
13.6
通讯作者：
Jue Wang;J. Ardelean;Yusong Bai;A. Steinhoff;M. Florian;F. Jahnke;Xiaodong Xu;M. Kira;J. Hone;X. Zhu
中科院分区：
文献类型：
--
作者：
Jue Wang;J. Ardelean;Yusong Bai;A. Steinhoff;M. Florian;F. Jahnke;Xiaodong Xu;M. Kira;J. Hone;X. Zhu
我们在二维WSe_2/MoSe_2异质双层膜中实现了从层间激子到电荷分离的电子/空穴等离子体的Mott跃迁。控制二维（2D）材料中的电荷密度是设计新的电子相和性质的有力方法。这种控制传统上是通过静电门控来实现的。在这里，我们报告了一种光学方法，用于产生高载流子密度，使用过渡金属二硫属化物异质双层，WSe 2/MoSe 2，与II型带对齐。通过调节光激发密度超过莫特阈值，我们实现了从层间激子到电荷分离的电子/空穴等离子体的相变，其中光激发的电子和空穴被定位到各个层。在脉冲和连续波激发条件下，可以维持高达4 × 1014 cm−2的高载流子密度。这些发现为二维异质双分子层中电子相位的光学控制打开了大门。
We realize Mott transition from interlayer exciton to charge-separated electron/hole plasmas in 2D WSe2/MoSe2 heterobilayers. Controlling charge density in two-dimensional (2D) materials is a powerful approach for engineering new electronic phases and properties. This control is traditionally realized by electrostatic gating. Here, we report an optical approach for generation of high carrier densities using transition metal dichalcogenide heterobilayers, WSe2/MoSe2, with type II band alignment. By tuning the optical excitation density above the Mott threshold, we realize the phase transition from interlayer excitons to charge-separated electron/hole plasmas, where photoexcited electrons and holes are localized to individual layers. High carrier densities up to 4 × 1014 cm−2 can be sustained under both pulsed and continuous wave excitation conditions. These findings open the door to optical control of electronic phases in 2D heterobilayers.