Theory of the evolution of 2Dband in the Raman spectra of monolayer and bilayer graphene with laser excitation energy

2009 ◽  
pp. n/a-n/a ◽  
Author(s):  
Hui Wang ◽  
Jinghan You ◽  
Lin Wang ◽  
Min Feng ◽  
Yufang Wang
Keyword(s):  
Excitation Energy ◽  
Raman Spectra ◽  
Laser Excitation ◽  
Bilayer Graphene

Raman spectra of twisted bilayer graphene close to the magic angle

2D Materials ◽  
2022 ◽  
Author(s):  
Tiago Campolina Barbosa ◽  
Andreij C. Gadelha ◽  
Douglas A. A. Ohlberg ◽  
Kenji Watanabe ◽  
Takashi Taniguchi ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Laser Excitation ◽  
Bilayer Graphene ◽  
Geometrical Model ◽  
Excitation Wavelength ◽  
Magic Angle ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Excitation Laser ◽  
Twisted Bilayer Graphene

Abstract In this work, we study the Raman spectra of twisted bilayer graphene samples as a function of their twist-angles (θ), ranging from 0.03º to 3.40º, where local θ are determined by analysis of their associated moiré superlattices, as imaged by scanning microwave impedance microscopy. Three standard excitation laser lines are used (457, 532, and 633 nm wavelengths), and the main Raman active graphene bands (G and 2D) are considered. Our results reveal that electron-phonon interaction influences the G band's linewidth close to the magic angle regardless of laser excitation wavelength. Also, the 2D band lineshape in the θ < 1º regime is dictated by crystal lattice and depends on both the Bernal (AB and BA) stacking bilayer graphene and strain soliton regions (SP) [1]. We propose a geometrical model to explain the 2D lineshape variations, and from it, we estimate the SP width when moving towards the magic angle.

Raman spectra of twisted CVD bilayer graphene

Carbon ◽  
2017 ◽  
Vol 123 ◽  
pp. 302-306 ◽  
Author(s):  
Pankaj Ramnani ◽  
Mahesh R. Neupane ◽  
Supeng Ge ◽  
Alexander A. Balandin ◽  
Roger K. Lake ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Bilayer Graphene

Probing the electrostatic environment of bilayer graphene using Raman spectra

2009 ◽  
Vol 80 (15) ◽  
Author(s):  
Paola Gava ◽  
Michele Lazzeri ◽  
A. Marco Saitta ◽  
Francesco Mauri
Keyword(s):  
Raman Spectra ◽  
Bilayer Graphene

R-Line Luminescence from Trace Amounts of Cr3+ in Aluminum Oxide and its Dependence on Sample Hydration

2002 ◽  
Vol 56 (8) ◽  
pp. 1055-1058 ◽  
Author(s):  
Chen Zuo ◽  
Paul W. Jagodzinski
Keyword(s):  
Aluminum Oxide ◽  
Raman Spectra ◽  
Laser Excitation ◽  
Sample Surface ◽  
Optical Spectra ◽  
Water Molecules ◽  
Commercial Products ◽  
Degree Of Hydration ◽  
Setting Reaction ◽  
Octahedral Sites

The R-line luminescence is observed in the Raman spectra of α- and γ-Al2O3 with chromium concentrations of less than 1 ppm. The same signals were previously used to monitor the setting reaction of dental cements. With laser excitation <690 nm, the R-line luminescence can be observed in the optical spectra of most commercial products containing α-Al2O3. It is found that the intensities of R-line signals are related to the degree of hydration of the α-Al2O3 sample, which can be explained by the formation of additional octahedral sites for Cr3+ near the sample surface involving oxygen atoms from the Al2O3 matrix and from absorbed water molecules.

Raman Apparatus Using Laser Excitation and Polarization Measurements. Rotational Spectrum of Fluorine

1969 ◽  
Vol 23 (1) ◽  
pp. 8-12 ◽  
Author(s):  
Howard H. Claassen ◽  
Henry Selig ◽  
Jacob Shamir
Keyword(s):  
Laser Beam ◽  
Raman Spectra ◽  
Laser Excitation ◽  
Scattered Light ◽  
Rotational Constant ◽  
Emission Lines ◽  
Optical Systems ◽  
Rotational Spectrum ◽  
Polarization Measurements

Various schemes are compared for measuring depolarization factors in Raman spectra with laser excitation. Optical systems are discussed for producing a laser beam free of unwanted emission lines and for focusing scattered light on the slit and on the detector. The rotational spectrum of gaseous F2 has been used to determine a rotational constant of Bo=0.8841 ±0.0006 cm−1, corresponding to r0=1.4168±0.0005 Å.

Dependence of the Raman spectra of drug substances upon laser excitation wavelength

2006 ◽  
Vol 37 (1-3) ◽  
pp. 335-341 ◽  
Author(s):  
Fiona C. Thorley ◽  
Kurt J. Baldwin ◽  
David C. Lee ◽  
David N. Batchelder
Keyword(s):  
Raman Spectra ◽  
Laser Excitation ◽  
Excitation Wavelength ◽  
Drug Substances

Resonance Raman Spectra of Aqueous Pollen Suspensions with 222.5–242.4-nm Pulsed Laser Excitation

1991 ◽  
Vol 45 (2) ◽  
pp. 307-311 ◽  
Author(s):  
R. Manoharan ◽  
E. Ghiamati ◽  
K. A. Britton ◽  
W. H. Nelson ◽  
J. F. Sperry
Keyword(s):  
Raman Spectra ◽  
Laser Excitation ◽  
Resonance Raman ◽  
Pulsed Laser ◽  
Resonance Raman Spectra
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