Exciton physics in 1D-2D heterostructures

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K23593
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0402:Nano/micro science, applied condensed matter physics, applied physics and engineering, and related fields
• Research Institution: Institute of Physical and Chemical Research
• 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)
• Project Period (FY): 2019-08-30 – 2022-03-31
• Keywords: carbon nanotube / hexagonal boron nitride / exciton / screening effect

Outline of Final Research Achievements

Hexagonal boron nitride (h-BN), a two-dimensional (2D) material, is atomically flat with low defect density, which is widely used to support other 2D materials for both electronics and photonics. We expect that the advantages of h-BN can also be utilized in mixed dimensional heterostructures, and carbon nanotubes (CNTs) would provide a unique opportunity in this context. The one-dimensional nature of CNTs results in enhanced Coulomb interactions, giving rise to tightly bound excitons that show photoluminescence (PL) at room temperature. CNTs directly attached on solid-state substrates such as SiO2/Si, however, suffers from the strong substrate quenching effect, hindering applications in all-solid-state optical devices. By using h-BN as a substrate, the quenching effect is expected to be suppressed. Moreover, excitons in CNTs are sensitive to the dielectric environment, and intimate contact with the 2D h-BN substrate could result in large modifications in excitonic energies.

Free Research Field

工学

Academic Significance and Societal Importance of the Research Achievements

These findings indicate that h-BN is an ideal solid-state subsatrate for the CNTs photonic devices and open a new path-way for manipulating excitons in CNTs.Moreover, we also observe that intimate contact with the h-BN substrate could result in large modifications in excitonic energies.