Abstract
As an ideal single-photon source, quantum dots (QDs) can play a unique role in the field of quantum information. Controlling QD exciton spontaneous emission can be achieved by anti-phase coupling between QD exciton dipole field and Au dipole field after QD film has been transferred onto the Si substrate covered by Au nanoparticles. In experiment, the studied InAs/GaAs QDs are grown by molecular beam epitaxy (MBE) on a (001) semi-insulation substrate. The films containing QDs with different GaAs thickness values are separated from the GaAs substrate by etching away the AlAs sacrificial layer and transferring the QD film to the silicon wafer covered by Au nanoparticles with a diameter of 50 nm. The distance <i>D</i> (thickness of GaAs) from the surface of the Au nanoparticles to the QD layer is 10, 15, 19, 25, and 35 nm, separately. A 640-nm pulsed semiconductor laser with a 40-ps pulse length is used to excite the QD samples for measuring QD exciton photoluminescence and time-resolved photoluminescence spectra at 5 K. It is found that when the distance <i>D</i> is 15–35 nm the spontaneous emission rate of exciton is suppressed. And when <i>D</i> is close to 19 nm, the QD spontaneous emission rate decreases to <inline-formula><tex-math id="M2">\begin{document}$ ~{10}^{-3} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20211863_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20211863_M2.png"/></alternatives></inline-formula>, which is consistent with the theoretical calculations. The physical mechanism of long-lived exciton luminescence observed in experiment lies in the fact that Au nanoparticles scatter the light field of the exciton radiation in the QD wetting layer, and the phase of the scattered field is opposite to the phase of the exciton radiation field. Therefore, the destructive interference between the exciton radiation field and scattering field of Au nanoparticles results in long-lived exciton emission observed in experiment.
Highlights
Controlling quantum dots (QDs) exciton spontaneous emission can be achieved by anti-phase coupling between QD exciton dipole field
Au dipole field after QD film has been transferred onto the Si substrate covered by
GaAs QDs are grown by molecular beam epitaxy
Summary
ZrS2量子点: 制备、结构及光学特性 ZrS2 quantum dots: Preparation, structure, and optical properties 物理学报. 基于超强耦合量子点-纳米机械振子系统的全光学质量传感 All-optical mass sensing based on ultra-strong coupling quantum dot-nanomechanical resonator system 物理学报. 量子点操控的光子探测和圆偏振光子发射 Single photon detection and circular polarized emission manipulated with individual quantum dot 物理学报. 将 InAs/GaAs 量子点样品薄膜置于覆盖有直径为 50 nm 的金 (Au) 纳米颗粒的硅衬底上, 可以调控量子 点激子的自发辐射速率. 本文在实验上使用金 (Au) 纳米颗粒抑制 InAs/ GaAs 量子点浸润层 (WL) 激子的自发辐射速率, 从而导致长寿命的浸润层激子被量子点俘获, 在量 子点中观察到长寿命激子的延迟发光现象. 采用氢氟酸 (HF) 选择蚀刻掉 AlAs 牺牲层, 将含有量子点的厚度 (100 + D) nm 的 GaAs 薄膜 与 GaAs 衬底分离, 然后将量子点薄膜样品转移到 覆盖有直径为 50 nm 的 Au 纳米颗粒的 Si 衬底上. 图 2(a), (c), (e), (g) 和 (i) 表示量子点薄膜样 品放置在 Au 纳米颗粒上后测量得到的 PL 光谱, 对应的 GaAs 层厚度 D 分别为 10, 15, 19, 25 和 35 nm. 在饱和激发功率下, 不同 GaAs 层厚度 D 的 PL 光谱强度不同.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.