2021 Fiscal Year Annual Research Report
Exciton physics in 1D-2D heterostructures
| Project/Area Number |
19K23593
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
Fang Nan 国立研究開発法人理化学研究所, 開拓研究本部, 基礎科学特別研究員 (50850509)
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| Project Period (FY) |
2019-08-30 – 2022-03-31
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| Keywords | carbon nanotubes / 2D materials / heterostructure / excitons |
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| Outline of Annual Research Achievements |
1) 2D/cavity hybrids. We report on an efficient control of microcavities with specially designed photonic crystal nanobeam structures. A new transfer technology using anthracene crystals is applied to prepare the atomically thin 2D material/cavity hybrid, which has a uniform morphology with minimal contamination. We observe a clear quantization behavior of the wavelength shift where each step represents an effect from an additional monolayer.By stacking and removing the transferred flakes, we demonstrate that the hybrids can be flexibly reconfigured benefitting from the versatile manipulation capabilities of the 2D materials.
2) WSe2/CNT hybrids. By using the anthracene transfer method, we successfully prepared the suspended WSe2/CNT heterostructures. We observe a strong interaction between trilayer WSe2 and (9,7) carbon nanotube. We find out that the A exciton excited in the WSe2 transfer to the nanotube, and emit the light at the E11 state. The exciton transfer process is found to be strongly affected by the WSe2 thickness because of the band structure change. CNTs with different chiralities are also prepared to form the heterostructure, and a clear chiral angle dependence is observed. A strong activation of k-momentum exciton is also confirmed, which is largely dependent on the excitation power. By measuring the time-resolved PL, we found that the lifetime of the transferred exciton increase to ~500 ps, which is ~10 times larger than the pristine E11 exciton lifetime.
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