Tag: 2D materials

Manipulating hyperbolic transient plasmons in a layered semiconductor

Anisotropic materials with oppositely signed dielectric tensors support hyperbolic polaritons, displaying enhanced electromagnetic localization and directional energy flow. *

However, the most reported hyperbolic phonon polaritons are difficult to apply for active electro-optical modulations and optoelectronic devices. *

In the nature communications letter “Manipulating hyperbolic transient plasmons in a layered semiconductor”, Rao Fu, Yusong Qu, Mengfei Xue, Xinghui Liu, Shengyao Chen, Yongqian Zhao, Runkun Chen, Boxuan Li, Hongming Weng, Qian Liu, Qing Dai and Jianing Chen report a dynamic topological plasmonic dispersion transition in black phosphorus (BP) via photo-induced carrier injection, i.e., transforming the iso-frequency contour from a pristine ellipsoid to a non-equilibrium hyperboloid. *

They introduce a promising approach to optically manipulate robust transient hyperbolic plasmons in the layered semiconductor black phosphorus using a dedicated ultrafast nanoscopy scheme. Optical pumping allows the BP’s IFCs to topologically transit from the pristine ellipsoid to the non-equilibrium hyperboloid, exhibiting exotic non-equilibrium hyperbolic plasmon properties, such as the optically tunable plasmonic dispersion and the coexistence of different transient plasmonic modes. *

Their work also demonstrates the peculiar transient plasmonic properties of the studied layered semiconductor, such as the ultrafast transition, low propagation losses, efficient optical emission from the black phosphorus’s edges, and the characterization of different transient plasmon modes. *

The results that Rao Fu et al. present may be relevant for the development of future optoelectronic applications. *

NanoWorld® ARROW-NCPt AFM probes with a Pt/Ir coating were used for the characterization with ultrafast nanoscopy. The pump and probe pulses were spatially overlapped on the Platinum/Iridium coated Arrow probe through a parabolic mirror of a commercial scattering-type scanning near-field optical microscope. *

Fig. 4 from Rao Fu et al. “Manipulating hyperbolic transient plasmons in a layered semiconductor”:Dynamic analysis of the transient plasmons. a Normalized near-field amplitude s3/s3,Si of a 280-nm-thick BP slab for twelve delay times τ. Scale bar, 1 µm. b Near-field amplitude curves for the corresponding twelve different delay times τ in a. c Dynamics of the relative near-field intensity of the first (∆S1) and the second bright strip (∆S2) in b. Opened circles are the experimental data, and solid lines are bi-exponential fitting for ∆S1 and exponential fitting for ∆S2, respectively. d Dynamics of the near-field amplitude s3 from the black circle in a. The inset displays the s3 at τ = −2 to 6 ps, and the dashed line marks the s3 level of the pristine state. NanoWorld® ARROW-NCPt AFM probes with a Pt/Ir coating were used for the characterization with ultrafast nanoscopy. The pump and probe pulses were spatially overlapped on the Pt/Ir coated Arrow probe through a parabolic mirror of a commercial scattering-type scanning near-field optical microscope.
Fig. 4 from Rao Fu et al. “Manipulating hyperbolic transient plasmons in a layered semiconductor”:
Dynamic analysis of the transient plasmons.
a Normalized near-field amplitude s3/s3,Si of a 280-nm-thick BP slab for twelve delay times τ. Scale bar, 1 µm. b Near-field amplitude curves for the corresponding twelve different delay times τ in a. c Dynamics of the relative near-field intensity of the first (∆S1) and the second bright strip (∆S2) in b. Opened circles are the experimental data, and solid lines are bi-exponential fitting for ∆S1 and exponential fitting for ∆S2, respectively. d Dynamics of the near-field amplitude s3 from the black circle in a. The inset displays the s3 at τ = −2 to 6 ps, and the dashed line marks the s3 level of the pristine state.

*Rao Fu, Yusong Qu, Mengfei Xue, Xinghui Liu, Shengyao Chen, Yongqian Zhao, Runkun Chen, Boxuan Li, Hongming Weng, Qian Liu, Qing Dai and Jianing Chen
Manipulating hyperbolic transient plasmons in a layered semiconductor
Nature Communications volume 15, Article number: 709 (2024)
DOI: https://doi.org/10.1038/s41467-024-44971-3

Please follow this external link to read the full article: https://rdcu.be/dBD85

The article “Manipulating hyperbolic transient plasmons in a layered semiconductor” by Rao Fu, Yusong Qu, Mengfei Xue, Xinghui Liu, Shengyao Chen, Yongqian Zhao, Runkun Chen, Boxuan Li, Hongming Weng, Qian Liu, Qing Dai and Jianing Chen is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third-party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.

Chemical switching of low-loss phonon polaritons in α-MoO3 by hydrogen intercalation

Phonon polaritons (PhPs) have attracted significant interest in the nano-optics communities because of their nanoscale confinement and long lifetimes. Although PhP modification by changing the local dielectric environment has been reported, controlled manipulation of PhPs by direct modification of the polaritonic material itself has remained elusive.*

In the article “Chemical switching of low-loss phonon polaritons in α-MoO3 by hydrogen intercalation” Yingjie Wu, Qingdong Ou, Yuefeng Yin, Yun Li, Weiliang Ma, Wenzhi Yu, Guanyu Liu, Xiaoqiang Cui, Xiaozhi Bao, Jiahua Duan, Gonzalo Álvarez-Pérez, Zhigao Dai, Babar Shabbir, Nikhil Medhekar, Xiangping Li, Chang-Ming Li, Pablo Alonso-González and Qiaoliang Bao demonstrate an effective chemical approach to manipulate PhPs in α-MoO3 by the hydrogen intercalation-induced perturbation of lattice vibrations.*

Their methodology establishes a proof of concept for chemically manipulating polaritons, offering opportunities for the growing nanophotonics community.*

The surface topography and near-field images presented in this article were captured using a commercial s-SNOM setup with a platinum iridium coated NanoWorld Arrow-NCPt AFM probe in tapping mode.*

Fig. 2 a) from “Chemical switching of low-loss phonon polaritons in α-MoO3 by hydrogen intercalation” by Yingjie Wu et al. : Reversible switching of PhPs in the L-RB of α-MoO3 a Schematic of the s-SNOM measurement and PhP propagation in a typical H-MoO3/α-MoO3 in-plane heterostructure. 2 a Schematic of the s-SNOM measurement and PhP propagation in a typical H-MoO3/α-MoO3 in-plane heterostructure. P
Fig. 2 a) from “Chemical switching of low-loss phonon polaritons in α-MoO3 by hydrogen intercalation” by Yingjie Wu et al. :
Reversible switching of PhPs in the L-RB of α-MoO3 a Schematic of the s-SNOM measurement and PhP propagation in a typical H-MoO3/α-MoO3 in-plane heterostructure.
2 a Schematic of the s-SNOM measurement and PhP propagation in a typical H-MoO3/α-MoO3 in-plane heterostructure. Please follow this external link for the full figure: https://www.nature.com/articles/s41467-020-16459-3/figures/2

*Yingjie Wu, Qingdong Ou, Yuefeng Yin, Yun Li, Weiliang Ma, Wenzhi Yu, Guanyu Liu, Xiaoqiang Cui, Xiaozhi Bao, Jiahua Duan, Gonzalo Álvarez-Pérez, Zhigao Dai, Babar Shabbir, Nikhil Medhekar, Xiangping Li, Chang-Ming Li, Pablo Alonso-González & Qiaoliang Bao
Chemical switching of low-loss phonon polaritons in α-MoO3 by hydrogen intercalation
Nature Communications volume 11, Article number: 2646 (2020)
DOI: https://doi.org/10.1038/s41467-020-16459-3

Please follow this external link to read the full article https://rdcu.be/b46eT

Open Access The article “ Chemical switching of low-loss phonon polaritons in α-MoO3 by hydrogen intercalation “ by Yingjie Wu, Qingdong Ou, Yuefeng Yin, Yun Li, Weiliang Ma, Wenzhi Yu, Guanyu Liu, Xiaoqiang Cui, Xiaozhi Bao, Jiahua Duan, Gonzalo Álvarez-Pérez, Zhigao Dai, Babar Shabbir, Nikhil Medhekar, Xiangping Li, Chang-Ming Li, Pablo Alonso-González and Qiaoliang Bao is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Self-assembled PCBM bilayers on graphene and HOPG examined by AFM and STM

In the article «Self-assembled PCBM bilayers on graphene and HOPG examined by AFM and STM” Yanlong Li, Chuanhui Chen, John Burton, Kyungwha Park, James R Heflin and Chenggang Tao demonstrate that PCBM molecules self-assemble into bilayer structures on graphene and HOPG substrates. They used Atomic Force Microscopy (AFM) and Scanning Tunneling Microscopy (STM), and analyzed the observed morphology by comparison to molecular models.*

The AFM measurements were carried out in a dark environment. NanoWorld™ Pointprobe® NCST AFM probes were used in soft tapping mode and simultaneous height and phase images were acquired and reproduced across multiple samples.*

The results of this study shed light on improvement of the energy efficiency in solar cells containing graphene and organic molecules, by increasing the donor–acceptor interface area and could provide valuable insight into fabrication of new hybrid, ordered structures for applications to organic solar cells.*

Figure 5. from “Self-assembled PCBM bilayers on graphene and HOPG examined by AFM and STM” by Yanlong Li et al.: AFM images of PCBM bilayer and size distributions of holes at different conditions. (a) AFM image of a PCBM bilayer before annealing. (b) AFM image of a PCBM bilayer after annealing at 140 °C. (c) AFM image of a PCBM bilayer after annealing at 160 °C. (d) Area distribution histogram of holes (without PCBM area) obtained from measurements of the area of holes in AFM images of before (green) and after annealing at 140 °C (dark red) and 160 °C (dark blue). Monolithic silicon cantilevers (NCST, NANO WORLD) with a spring constant of 7.4 N m−1, first longitudinal resonance frequencies between 120 and 205 kHz, and nominal tip radius of 8 nm were employed in soft tapping mode. Simultaneous height and phase images were acquired and reproduced across multiple samples.
Figure 5. from “Self-assembled PCBM bilayers on graphene and HOPG examined by AFM and STM” by Yanlong Li et al.: AFM images of PCBM bilayer and size distributions of holes at different conditions. (a) AFM image of a PCBM bilayer before annealing. (b) AFM image of a PCBM bilayer after annealing at 140 °C. (c) AFM image of a PCBM bilayer after annealing at 160 °C. (d) Area distribution histogram of holes (without PCBM area) obtained from measurements of the area of holes in AFM images of before (green) and after annealing at 140 °C (dark red) and 160 °C (dark blue).

*Yanlong Li, Chuanhui Chen, John Burton, Kyungwha Park, James R Heflin, Chenggang Tao
Self-assembled PCBM bilayers on graphene and HOPG examined by AFM and STM
Nanotechnology, Volume 29, Number 18 (2018)
DOI: https://doi.org/10.1088/1361-6528/aab00a

Open Access The article “Self-assembled PCBM bilayers on graphene and HOPG examined by AFM and STM” by Yanlong Li et al. is licensed under a Creative Commons Attribution 3.0 International License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. To view a copy of this license, visit https://creativecommons.org/licenses/by/3.0/