Upconverted electroluminescence via Auger scattering of interlayer excitons in van der Waals heterostructures
Upconverted electroluminescence via Auger scattering of interlayer excitons in van der Waals heterostructures
复制标题
DOI：
10.1038/s41467-019-10323-9
复制
发表时间：
2019-05-27
影响因子：
16.6
通讯作者：
Kozikov, A.
中科院分区：
文献类型：
--
作者：
Binder, J.;Howarth, J.;Kozikov, A.
载流子-载流子相互作用的有趣物理现象同样影响发光器件的运行，刺激了对高激发载流子密度的半导体结构的研究，这是在大泵浦速率或具有长寿命电子空穴对的系统中可达到的极限。通过将载流子电注入实空间和k空间中间接的WSe2/MoS2 II型异质结构中，我们建立了大量典型的光学静音层间激子。在这里，我们揭示了它们的发射光谱，并表明发射能量可以通过施加的电场进行调节。当通过在WSe2和MoS2之间引入hBN间隔物来抑制辐射复合率而进一步增加粒子数时，俄歇型和激子-激子湮灭过程变得重要。这些过程通过观察上转换发射来追踪，表明在非辐射俄歇过程中获得能量的激子可以被恢复并辐射重组。
The intriguing physics of carrier-carrier interactions, which likewise affect the operation of light emitting devices, stimulate the research on semiconductor structures at high densities of excited carriers, a limit reachable at large pumping rates or in systems with long-lived electron-hole pairs. By electrically injecting carriers into WSe2/MoS2 type-II heterostructures which are indirect in real and k-space, we establish a large population of typical optically silent interlayer excitons. Here, we reveal their emission spectra and show that the emission energy is tunable by an applied electric field. When the population is further increased by suppressing the radiative recombination rate with the introduction of an hBN spacer between WSe2 and MoS2, Auger-type and exciton-exciton annihilation processes become important. These processes are traced by the observation of an up-converted emission demonstrating that excitons gaining energy in non-radiative Auger processes can be recovered and recombine radiatively.