静水压力调谐Ag纳米颗粒散射场下量子点激子寿命  

Exciton lifetime of quantum dots under hydrostatic pressure tuned scattering field Ag nanoparticles

作　　者：黄君辉 李元和 王健 李叔伦 倪海桥[1,2] 牛智川 窦秀明[1,2] 孙宝权 Huang Jun-Hui;Li Yuan-He;Wang Jian;Li Shu-Lun;Ni Hai-Qiao;Niu Zhi-Chuan;Dou Xiu-Ming;Sun Bao-Quan(State Key Laboratory of Superlattices and Microstructures,Institute of Semiconductors,Chinese Academy of Sciences,Beijing 100083,China;College of Materials Science and Optoelectronic Technology,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院半导体研究所,超晶格国家重点实验室,北京100083 [2]中国科学院大学材料科学与光电技术学院,北京100049

出　　处：《物理学报》2022年第24期350-357,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61827823,11974342)资助的课题。

摘　　要：将InAs/GaAs量子点薄膜样品转移到Ag纳米颗粒覆盖的Si衬底上,然后将样品放到金刚石对顶砧压力腔室内.在1.09—1.98 GPa的压力范围内,测量了量子点激子的荧光光谱和时间分辨光谱.实验结果显示,随着静水压力的增大,激子的发光波长蓝移,激子的发光寿命从(41±3)×10 ns延长到(120±4)×10 ns,再减短到(7.6±0.2)ns,在激子发光波长为797.49nm时,寿命达到最长的(120±4)×10 ns.相比没有Ag纳米颗粒影响的InAs/GaAs量子点中的激子寿命约1ns,激子的寿命延长了约1200倍.其物理机制为量子点浸润层中激子的辐射场和Ag纳米颗粒的散射场之间发生相消干涉,抑制了浸润层中激子的自发辐射,这些长寿命的浸润层激子将扩散到量子点中,并辐射复合发光,从而观察到量子点激子的长寿命衰变曲线.这一实验结果与基于在散射场下的偶极子辐射模型计算结果一致.In the past few decades,the studies of exciton emissions coupled with the metal nanoparticles have mainly focused on the enhancing exciton radiation and reducing exciton lifetime by near-field coupling interactions between excitons and metal nanoparticles.Only in recent years has the plasmon-field-induced to extend exciton lifetime(inhibition of the exciton emission)been reported.Experimentally,for observing a long-lifetime exciton state it needs to satisfy a condition of kz~1,instead of near-field condition of kz(?)1,where k=2πn/λis the wavevector,n is the refractive index,A is the wavelength,and z is the separation distance between the emitter and metal nanoparticle.Thus,in this paper,we tune the exciton emission wavelength by applying hydrostatic pressure to achieve the condition of kz~1 in order to in detail investigate the coupling between excitons and metal nanoparticles.The studied InAs/GaAs quantum dot(QD)sample is grown by molecular beam epitaxy on a(001)semi-insulating GaAs substrate.After the AlAs sacrificial layer is etched with hydrofluoric acid,the QD film sample is transferred onto an Si substrate covered with Ag nanoparticles.Then the sample is placed in the diamond anvil cell device combined with a piezoelectric ceramic.In this case we can measure the photoluminescence and time-resolved photoluminescence spectra of the QD sample under different pressures.It is found that the observed longest exciton lifetime is(120±4)×10 ns at a pressure of 1.38 GPa,corresponding the exciton emission wavelength of 797.49 nm,which is about 1200 times longer than the exciton lifetime of~1 ns in QDs without the influence of Ag nanoparticles.The experimental results can be understood based on the destructive interference between the quantum dot exciton radiation field and the scattering field of metal nanoparticles.This model proposes a convenient way to increase the emission lifetime of dipoles on a large scale,and is expected to be applied to quantum information processing,optoelectronic applications,fundamenta

关 键 词：INAS/GAAS量子点 自发辐射速率 AG纳米颗粒 长寿命激子 静水压力 

分 类 号：O413[理学—理论物理]