Bright trion emission from semiconductor nanoplatelets
Bright trion emission from semiconductor nanoplatelets
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DOI：
10.1103/physrevmaterials.4.056006
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发表时间：
2020-05
影响因子：
3.4
通讯作者：
Lintao Peng;M. Otten;A. Hazarika;I. Coropceanu;M. Cygorek;G. Wiederrecht;P. Hawrylak;D. Talapin;Xuedan Ma
中科院分区：
文献类型：
--
作者：
Lintao Peng;M. Otten;A. Hazarika;I. Coropceanu;M. Cygorek;G. Wiederrecht;P. Hawrylak;D. Talapin;Xuedan Ma
trion是一种准粒子，包含一个激子和一个额外的电荷载流子，它为产生可用于开发量子网络的自旋光子界面提供了独特的机会。Trions也被积极寻求用于集成光电器件，包括光电器件，光电探测器和自旋电子学。然而，在强限制的低维材料中形成trions通常被认为是有害的。这是因为由于主要的非辐射俄歇复合过程，这种材料中的三电子发射通常被禁止。半导体纳米片具有在厚度方向上的强限制和扩展的横向几何形状，表现出大的激子相干尺寸和降低的载流子-载流子相互作用，这可以实现前所未有的三电子性质。在这里，我们在低温下进行个别的CdSe纳米片的光学光谱研究，并观察到明亮的trion发射与中性激子发射的强度相当。我们进行载流子动力学研究的纳米片，并发现，由于其扩展的横向几何形状，在低温下的纳米片的快速辐射衰减率是可比的抑制俄歇复合率，导致明亮的trion发射。我们的紧束缚理论进一步揭示了不同的尺寸可调的trion发射的纳米片，这是有利于有效的trion发射。这些性质使得半导体纳米片成为光电和量子逻辑器件的光子源的潜在候选者。
The trion, a quasiparticle comprising one exciton and an additional charge carrier, offers unique opportunities for generating spin-photon interfaces that can be used in developing quantum networks. Trions are also actively sought after for integrated optoelectronic devices including photovoltaics, photodetectors, and spintronics. However, formation of trions in strongly confined low-dimensional materials is often deemed detrimental. This is because trion emission in such materials is typically prohibited due to the predominant nonradiative Auger recombination processes. Semiconductor nanoplatelets with their strong confinement in the thickness direction and extended lateral geometries exhibit large exciton coherence sizes and reduced carrier-carrier interactions that may enable unprecedented trion properties. Here, we perform optical spectroscopic studies of individual CdSe nanoplatelets at cryogenic temperatures and observe bright trion emission with intensities comparable to that of neutral exciton emission. We perform carrier dynamics studies of the nanoplatelets and find that due to their extended lateral geometry, the fast radiative decay rate of the nanoplatelets at cryogenic temperatures is comparable to the inhibited Auger recombination rate, leading to the bright trion emission. Our tight-binding theory further reveals distinct size-tunable trion emission in the nanoplatelets that is advantageous for efficient trion emission. These properties make semiconductor nanoplatelets potential candidates as photon sources for optoelectronic and quantum logic devices.