Japanese page is here.
Japanese page is here.
M. Xue et al., Appl. Phys. Lett (2023)
The excited states of excitons were observed with high sensitivity by lock-in detection of reflected light modulated by applying gate voltage. We detected the 2s state, whose signal is usually a weak, not only for excitons but also for charged excitons. In the future, we will selectively detect excitons from local states such as Moire excitons.
S. Zhang et al., Nanoscale (2023)
We report that photocurrent flows in van der Waals heterostructures even without a PN junction; the IV characteristic is linear, and a photocurrent of 28 nA flows under light irradiation even with zero bias. Photocurrent mapping revealed that this photocurrent originates from the stacking structure.
Y. Murai et al., ACS Nano (2021)
We have developed a post doping method for two-dimensional crystals. We can dope various elements substitutionally into frameworks of 2D crystals by this method, which will lead to various functional devices and new 2D crystals.
T. Hotta et al., ACS Nano (2021) and arXiv submitted on 4 Jun. (2020)
We have established a new method for the preparation of ultraflat 2D crystals. An ultraflat monolayer MoSe2 prepared shows extremely sharp optical transitions and enhanced exciton-exciton collisions, providing an ideal playground for investigating many-body effects in 2D systems.
T. Hotta et al., Phys. Rev. B. (2020) and arXiv submitted on 28 Apr. (2019)
We have obesrved exciton diffusion in a 2D crystal, hBN/MoSe2/hBN.
We found that the number of scattering sources was small in a high-quality 2D heterostructure, leading to high exciton mobility at low temperatures.
S. Zhao et al., Phys. Rev. Lett. (2020) and arXiv submitted on 22 Jun. (2019)
We have successfully observed a drastic change in the electronic bandstructure of a DWCNT through Rayleigh scattering spectroscopy on individual DWCNTs.
The change in electronic bandstructure arises from long-period moire potential.
This paper was selected as an Editor's suggestion in PRL!
Uchiyama, Y. et al., npj 2D materials & applications (2019)
We found that a momentum-forbidden dark state is more stable than the bright exciton in this system due to bandstructure modulation arising from orbital hybridization between MoS2 and hBN. In hBN/MoS2/hBN heterostructures, the most stable exciton is not the bright exciton anymore!
Okada, M. et al., ACS Nano 12, 3, 2498 (2018)
The origin of low-energy PL peaks found in PL spectra of WS2/MoS2 was addressed.
We found that, in a multi-valley system, momentum-forbidden interlayer excitons plays an important role.
Okada, M. et al., Scientific Reports, 7, 322 (2017)
We have observed the efficient formation of biexcitons in WS2/hBN. Enhanced exciton diffusion plays a crucial role in the formation of biexcitons.
Wang, Q. et al., ACS Nano, 10, 1475 (2016)
We have performed in-situ measurements of electronic transport of graphene nanoribbons (GNRs) in a TEM.
In this work, we found that the thinning of a graphene nanoribbon down to ca. 2 nm has led to the opening bandgap of ~ several hundreds of milli-electron volts.
Hotta, T. et al., Appl. Phys. Lett., 109, 133101 (2016)
We have succesfully grown monolayer NbSe2 by molecular beam epitaxy method. This paper was selected as a cover picture of Appl. Phys. Lett.!
Okada, M. et al., ACS Nano, 8, 8273 (2014)
We have realized WS2/hBN heterostructures with clean interface by the multi-furnace chemical vapor deposition method.
We found that ultraflat hBN can strongly suppress inhomogeneous broadening in PL spectra of monolayer WS2.
