Long-Lived Direct and Indirect Interlayer Excitons in van der Waals Heterostructures
Long-Lived Direct and Indirect Interlayer Excitons in van der Waals Heterostructures
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DOI：
10.1021/acs.nanolett.7b01304
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发表时间：
2017-09-01
期刊：
影响因子：
10.8
通讯作者：
Wurstbauer, Ursula
中科院分区：
文献类型：
--
作者：
Miller, Bastian;Steinhoff, Alexander;Wurstbauer, Ursula
我们报告了在由单层 MoSe2 和 WSe2 组成的异质结构中层间激子的低温光致发光中观察到双峰结构。两个峰均表现出数十纳秒至 100 ns 的长光致发光寿命，验证了激子的层间性质。两个峰的能量和线宽显示出不同寻常的温度和功率依赖性。虽然低能量峰在低功率和低温下的光谱中占主导地位，但高能量峰在高功率和温度下占主导地位。我们通过在倒易空间中间接或准直接的两种层间激子来解释这一发现。我们的结果为范德华异质结构中长期存在的层间态以及可能的玻色多体相互作用提供了基本见解。
We report the observation of a doublet structure in the low-temperature photoluminescence of interlayer excitons in hetero-structures consisting of monolayer MoSe2 and WSe2. Both peaks exhibit long photoluminescence lifetimes of several tens of nanoseconds up to 100 ns verifying the interlayer nature of the excitons. The energy and line width of both peaks show unusual temperature and power dependences. While the low-energy peak dominates the spectra at low power and low temperatures, the high-energy peak dominates for high power and temperature. We explain the findings by two kinds of interlayer excitons being either indirect or quasi-direct in reciprocal space. Our results provide fundamental insights into long-lived interlayer states in van der Waals heterostructures with possible bosonic many-body interactions.