Chin. Phys. B, 2021, Vol. 30(9): 097805    DOI: 10.1088/1674-1056/ac0818
 CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES Prev   Next

# Exciton emission dynamics in single InAs/GaAs quantum dots due to the existence of plasmon-field-induced metastable states in the wetting layer

Junhui Huang(黄君辉)1,2, Hao Chen(陈昊)1,2, Zhiyao Zhuo(卓志瑶)1,2, Jian Wang(王健)1,2, Shulun Li(李叔伦)1,2, Kun Ding(丁琨)1,2, Haiqiao Ni(倪海桥)1,2, Zhichuan Niu(牛智川)1,2,3, Desheng Jiang(江德生)1, Xiuming Dou(窦秀明)1,2,†, and Baoquan Sun(孙宝权)1,2,3,‡
1 State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;
2 College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China;
3 Beijing Academy of Quantum Information Sciences, Beijing 100193, China
Abstract  A very long lifetime exciton emission with non-single exponential decay characteristics has been reported for single InA-s/GaAs quantum dot (QD) samples, in which there exists a long-lived metastable state in the wetting layer (WL) through radiative field coupling between the exciton emissions in the WL and the dipole field of metal islands. In this article we have proposed a new three-level model to simulate the exciton emission decay curve. In this model, assuming that the excitons in a metastable state will diffuse and be trapped by QDs, and then emit fluorescence in QDs, a stretched-like exponential decay formula is derived as $I\left( t \right)=A\, t^{\beta -1}{\rm e}^{-\left( rt \right)^{\beta }}$, which can describe well the long lifetime decay curve with an analytical expression of average lifetime $\langle\tau\rangle=\frac{1}{r}\mathrm{\Gamma } ( \frac{1}{\beta }+1 )$，where $\Gamma$ is the Gamma function. Furthermore, based on the proposed three-level model, an expression of the second-order auto-correlation function $g^{2}\left( t \right)$ which can fit the measured $g^{2}\left( t \right)$ curve well, is also obtained.
Keywords:  quantum dots      collective excitations      charge carriers      time resolved spectroscopy
Received:  07 May 2021      Revised:  01 June 2021      Accepted manuscript online:  04 June 2021
 PACS: 78.67.Hc (Quantum dots) 73.20.Mf (Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)) 73.50.Gr (Charge carriers: generation, recombination, lifetime, trapping, mean free paths) 78.47.D- (Time resolved spectroscopy (>1 psec))
Fund: Project supported by the National Key Research and Development Program of China (Grant No. 2016YFA0301202) and the National Natural Science Foundation of China (Grant Nos. 61827823 and 11974342).
Corresponding Authors:  Xiuming Dou, Baoquan Sun     E-mail:  xmdou04@semi.ac.cn;bqsun@semi.ac.cn