Direct and Indirect Interlayer Excitons in a van der Waals Heterostructure of hBN/WS2/MoS2/hBN
| Autor: | Ryo Kitaura, Tetsuki Saito, Takashi Taniguchi, Boris I. Yakobson, Alex Kutana, Yusuke Kureishi, Kenji Watanabe, Hisanori Shinohara, Yu Kobayashi, Sachin Gupta, Yuika Saito, Mitsuhiro Okada, Yasumitsu Miyata |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Photoluminescence Condensed matter physics Pl spectra Exciton General Engineering General Physics and Astronomy Hexagonal boron nitride Heterojunction 02 engineering and technology Electronic structure 021001 nanoscience & nanotechnology 01 natural sciences symbols.namesake 0103 physical sciences Monolayer symbols General Materials Science van der Waals force 010306 general physics 0210 nano-technology |
| Zdroj: | ACS Nano. 12:2498-2505 |
| ISSN: | 1936-086X 1936-0851 |
| Popis: | A van der Waals (vdW) heterostructure composed of multivalley systems can show excitonic optical responses from interlayer excitons that originate from several valleys in the electronic structure. In this work, we studied photoluminescence (PL) from a vdW heterostructure, WS2/MoS2, deposited on hexagonal boron nitride (hBN) flakes. PL spectra from the fabricated heterostructures observed at room temperature show PL peaks at 1.3–1.7 eV, which are absent in the PL spectra of WS2 or MoS2 monolayers alone. The low-energy PL peaks we observed can be decomposed into three distinct peaks. Through detailed PL measurements and theoretical analysis, including PL imaging, time-resolved PL measurements, and calculation of dielectric function e(ω) by solving the Bethe–Salpeter equation with G0W0, we concluded that the three PL peaks originate from direct K–K interlayer excitons, indirect Q−Γ interlayer excitons, and indirect K−Γ interlayer excitons. |
| Databáze: | OpenAIRE |
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