Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International

Wikipedia Affiliate Button

Home > Press > Quantitatively understanding of angle-resolved polarized Raman scattering from black phosphorus

Abstract:
For anisotropic crystals, it has been known for many years that the birefringence effect rising from anisotropic refractive index should be considered for angle-resolved polarized Raman (ARPR) intensity. For opaque anisotropic crystals (OAC), not only the birefringence effect but also the dichroism effect from anisotropic absorption is responsible for ARPR intensity. With boomed emergence of in-plane anisotropic layered materials (ALMs), e.g., black phosphorus (BP), the investigations of their ARPR intensity have received great attention, which are commonly fitted by its Raman tensor and polarization of incident laser and scattered signal outside the crystals with a fitted complex Raman tensor due to dichroism or a fitted birefringence-induced phase delay. However, these approaches cannot be applicable to the case of ARPR intensity at oblique laser incidence because of the complex depth-dependent polarization and intensity of incident laser and scattered signal inside ALMs, and additional angle-dependent reflection and refraction at the interface between ALM lakes and air. Fundamentally, only real Raman tensor is generally involved if no magnetic perturbation occurs. Thus, this leaves an open question whether it is possible to reproduce ARPR intensity of OAC by only the real Raman tensor, especially for emergent ALMs.

Quantitatively understanding of angle-resolved polarized Raman scattering from black phosphorus

Beijing, China | Posted on September 11th, 2020

Recently, a research team led by Prof. Ping-Heng Tan from Institute of Semiconductors, Chinese Academy of Sciences proposed a so-called birefringence-linear-dichroism (BLD) model to quantitively understand the ARPR intensity at both normal and oblique laser incidences on in-plane ALMs, by taking the bulk black phosphorus (BP) as an example. The depth-dependent polarization and intensity of incident laser and scattered signal induced by birefringence and linear dichroism are considered by complex refractive indexes along three principle axes, which is experimentally determined by the incident-angle resolved reflectivity. The experimental ARPR intensity can be well reproduced by the same set of real Raman tensors for a certain laser excitation, which are obtained from the relative Raman intensity along its principle axes. No fitting parameter is needed.

Fig.1 shows the setup for ARPR measurements at laser normal incidence and the corresponding ARPR intensity excited by 488 nm and 532 nm lasers. The good agreement between the calculated results (solid lines) experimental data (open circles) indicates that the ARPR intensity in ALMs can be quantitatively understand by the real Raman tensor once the birefringence and linear dichroism effects are considered based on the BLD model. In Fig.2, the ARPR intensity at oblique laser incidence can also be well reproduced by the same set of Raman tensors without any fitting parameters, which implies that the BLD model is possible to quantitatively reproduce the ARPR intensity of all ALMs for a given excitation wavelength under any scattering and polarization configurations.

The results suggest that the previously reported ARPR intensity of ultrathin ALM flakes deposited on a multilayered substrate at normal laser incidence can be also understood based on the BLD model by considering the depth-dependent polarization and intensity of incident laser and scattered Raman signal induced by both birefringence and linear dichroism effects within ALM flakes and the interference effects in the multilayered structures, which are dependent on the excitation wavelength, thickness of ALM flakes and dielectric layers of the substrate. This work can be generally applicable to any OAC, offering a promising route to predict and manipulate the polarized behaviors of related phonons.

###

This work was supported by the National Key Research and Development Program of China (2016YFA0301204), the National Natural Science Foundation of China (11874350 and 51702352), the CAS Key Research Program of Frontier Sciences (ZDBS-LYSLH004), China Postdoctoral Science Foundation (2019TQ0317), Youth Innovation Promotion Association Chinese Academy of Sciences (2020354).

####

For more information, please click here

Contacts:
Ping-Heng Tan

Copyright © Science China Press

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

See the article for more details:

Related News Press

News and information

Nano-microscope gives first direct observation of the magnetic properties of 2D materials: Discovery means new class of materials and technologies September 18th, 2020

Physicists make electrical nanolasers even smaller September 18th, 2020

Shape matters for light-activated nanocatalysts - Study: Pointed tips on aluminum 'octopods' increase catalytic reactivity September 18th, 2020

Aberrant electronic and structural alterations in pressure tuned perovskite NaOsO3 September 18th, 2020

Govt.-Legislation/Regulation/Funding/Policy

Nano-microscope gives first direct observation of the magnetic properties of 2D materials: Discovery means new class of materials and technologies September 18th, 2020

Physicists make electrical nanolasers even smaller September 18th, 2020

Shape matters for light-activated nanocatalysts - Study: Pointed tips on aluminum 'octopods' increase catalytic reactivity September 18th, 2020

Fast calculation dials in better batteries: Analytical model from Rice University helps researchers fine-tune battery performance September 16th, 2020

Possible Futures

Nano-microscope gives first direct observation of the magnetic properties of 2D materials: Discovery means new class of materials and technologies September 18th, 2020

Physicists make electrical nanolasers even smaller September 18th, 2020

Shape matters for light-activated nanocatalysts - Study: Pointed tips on aluminum 'octopods' increase catalytic reactivity September 18th, 2020

Aberrant electronic and structural alterations in pressure tuned perovskite NaOsO3 September 18th, 2020

Discoveries

Nano-microscope gives first direct observation of the magnetic properties of 2D materials: Discovery means new class of materials and technologies September 18th, 2020

Physicists make electrical nanolasers even smaller September 18th, 2020

Shape matters for light-activated nanocatalysts - Study: Pointed tips on aluminum 'octopods' increase catalytic reactivity September 18th, 2020

Aberrant electronic and structural alterations in pressure tuned perovskite NaOsO3 September 18th, 2020

Materials/Metamaterials

Nano-microscope gives first direct observation of the magnetic properties of 2D materials: Discovery means new class of materials and technologies September 18th, 2020

Aberrant electronic and structural alterations in pressure tuned perovskite NaOsO3 September 18th, 2020

Get diamonds, take temperature: Quantum thermometer using nanodiamonds senses a 'fever' in tiny worms C. elegans September 11th, 2020

Boundaries no barrier for thermoelectricity: Rice researchers find potentially useful electrical phenomenon in gold nanowires September 8th, 2020

Announcements

Nano-microscope gives first direct observation of the magnetic properties of 2D materials: Discovery means new class of materials and technologies September 18th, 2020

Physicists make electrical nanolasers even smaller September 18th, 2020

Shape matters for light-activated nanocatalysts - Study: Pointed tips on aluminum 'octopods' increase catalytic reactivity September 18th, 2020

Aberrant electronic and structural alterations in pressure tuned perovskite NaOsO3 September 18th, 2020

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters

Who stole the light? Self-induced ultrafast demagnetization limits the amount of light diffracted from magnetic samples at soft x-ray energies September 18th, 2020

Nano-microscope gives first direct observation of the magnetic properties of 2D materials: Discovery means new class of materials and technologies September 18th, 2020

Physicists make electrical nanolasers even smaller September 18th, 2020

Shape matters for light-activated nanocatalysts - Study: Pointed tips on aluminum 'octopods' increase catalytic reactivity September 18th, 2020

Photonics/Optics/Lasers

Who stole the light? Self-induced ultrafast demagnetization limits the amount of light diffracted from magnetic samples at soft x-ray energies September 18th, 2020

Physicists make electrical nanolasers even smaller September 18th, 2020

A phonon laser - coherent vibrations from a self-breathing resonator September 11th, 2020

Round nanoparticles improve quality factors of surface lattice resonances: Study August 28th, 2020

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project