Lubin Gur, Tenne Ron, Ulku Arin Can, Antolovic Ivan Michel, Burri Samuel, Karg Sean, Yallapragada Venkata Jayasurya, Bruschini Claudio, Charbon Edoardo, Oron Dan
Deptartment of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel.
Department of Physics and Center for Applied Photonics, University of Konstanz, Konstanz D-78457, Germany.
Nano Lett. 2021 Aug 25;21(16):6756-6763. doi: 10.1021/acs.nanolett.1c01291. Epub 2021 Aug 16.
Multiply excited states in semiconductor quantum dots feature intriguing physics and play a crucial role in nanocrystal-based technologies. While photoluminescence provides a natural probe to investigate these states, room-temperature single-particle spectroscopy of their emission has proved elusive due to the temporal and spectral overlap with emission from the singly excited and charged states. Here, we introduce biexciton heralded spectroscopy enabled by a single-photon avalanche diode array based spectrometer. This allows us to directly observe biexciton-exciton emission cascades and measure the biexciton binding energy of single quantum dots at room temperature, even though it is well below the scale of thermal broadening and spectral diffusion. Furthermore, we uncover correlations hitherto masked in ensembles of the biexciton binding energy with both charge-carrier confinement and fluctuations of the local electrostatic potential. Heralded spectroscopy has the potential of greatly extending our understanding of charge-carrier dynamics in multielectron systems and of parallelization of quantum optics protocols.
半导体量子点中的多重激发态具有引人入胜的物理特性，在基于纳米晶体的技术中起着至关重要的作用。虽然光致发光为研究这些状态提供了一种自然的探针，但由于与单重激发态和带电态发射的时间和光谱重叠，其在室温下的单粒子发射光谱一直难以实现。在此，我们介绍了一种由基于单光子雪崩二极管阵列的光谱仪实现的双激子预示光谱。这使我们能够直接观察双激子 - 激子发射级联，并在室温下测量单个量子点的双激子结合能，尽管该能量远低于热展宽和光谱扩散的尺度。此外，我们还揭示了迄今在双激子结合能的集合中被掩盖的与电荷载流子限制和局部静电势波动的相关性。预示光谱有潜力极大地扩展我们对多电子系统中电荷载流子动力学的理解以及量子光学协议并行化的理解。
