Temperature-Dependent Exciton Dynamics in a Single GaAs Quantum Ring and a Quantum Dot

Heedae Kim; Jong Su Kim; Jin Dong Song

doi:10.3390/nano12142331

Temperature-Dependent Exciton Dynamics in a Single GaAs Quantum Ring and a Quantum Dot

Nanomaterials (Basel). 2022 Jul 7;12(14):2331. doi: 10.3390/nano12142331.

Authors

Heedae Kim¹, Jong Su Kim², Jin Dong Song³

Affiliations

¹ School of Semiconductor Science, Technology and Semiconductor Physics Research Center, Jeonbuk National University, Jeonju 561-756, Korea.
² Department of Physics, Yeungnam University, Gyeongsan 38541, Korea.
³ Center for Opto-Electronic Convergence Systems, Korea Institute of Science and Technology, Seoul 136-791, Korea.

Abstract

Micro-photoluminescence was observed while increasing the excitation power in a single GaAs quantum ring (QR) at 4 K. Fine structures at the energy levels of the ground (N = 1) and excited (N = 2) state excitons exhibited a blue shift when excitation power increased. The excited state exciton had a strong polarization dependence that stemmed from the asymmetric localized state. According to temperature-dependence measurements, strong exciton-phonon interaction (48 meV) was observed from an excited exciton state in comparison with the weak exciton-phonon interaction (27 meV) from the ground exciton state, resulting from enhanced confinement in the excited exciton state. In addition, higher activation energy (by 20 meV) was observed for the confined electrons in a single GaAs QR, where the confinement effect was enhanced by the asymmetric ring structure.

Keywords: exciton; fine structures; localized states; photoluminescence; polarization dependence; quantum dot structure; quantum ring structure; strong confinement.

Grants and funding

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (NRF-2021R1|1A3059963, NRF-2018M3A7B4069996). This study was supported by Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2014R1A6A1031189), the program of quantum sensor core technology through IITP (MSIT grant no. 20190004340011001).