scholarly journals Optical properties of biased bilayer graphene due to gap parameter effects

2020 ◽  
Vol 68 ◽  
pp. 321-329
Author(s):  
Bahram Maleki ◽  
Hamed Rezania
Author(s):  
Y. H. Ho ◽  
J. Y. Wu ◽  
Y. H. Chiu ◽  
J. Wang ◽  
M. F. Lin

The electronic and optical properties of monolayer and bilayer graphene are investigated to verify the effects of interlayer interactions and external magnetic field. Monolayer graphene exhibits linear bands in the low-energy region. Then the interlayer interactions in bilayers change these bands into two pairs of parabolic bands, where the lower pair is slightly overlapped and the occupied states are asymmetric with respect to the unoccupied ones. The characteristics of zero-field electronic structures are directly reflected in the Landau levels. In monolayer and bilayer graphene, these levels can be classified into one and two groups, respectively. With respect to the optical transitions between the Landau levels, bilayer graphene possesses much richer spectral features in comparison with monolayers, such as four kinds of absorption channels and double-peaked absorption lines. The explicit wave functions can further elucidate the frequency-dependent absorption rates and the complex optical selection rules. These numerical calculations would be useful in identifying the optical measurements on graphene layers.


2011 ◽  
Vol 115 (33) ◽  
pp. 16619-16624 ◽  
Author(s):  
Amirhasan Nourbakhsh ◽  
Mirco Cantoro ◽  
Alexander V. Klekachev ◽  
Geoffrey Pourtois ◽  
Tom Vosch ◽  
...  

RSC Advances ◽  
2014 ◽  
Vol 4 (61) ◽  
pp. 32117-32126 ◽  
Author(s):  
Cheng-Peng Chang

An analytical approach is developed to access the exact energy spectrum, wave functions, dipole matrix element (Mfi) and absorption spectra (A(ω)) of gated Bernal bilayer graphene.


2020 ◽  
Vol 12 ◽  
Author(s):  
Abhay Kumar Singh ◽  
Tien-Chien Jen

Aims: To address the physical properties of the growing research topic based on inorganic and organic composite materials under the glassy regime. The incorporation of a small amount of organic content in inorganic chalcogenide alloy could be an interesting topic for the investigation. Such composite materials optical and structural properties could define their prospective use. Objectives: Considering prospective utility of the inorganic and organic composite materials this report key goal to demonstrate the structural and optical properties, like, absorption spectra, extinction coefficient (k), real dielectric constant (εʹ), imaginary dielectric constant (εʹʹ), refractive index (n), absorption coefficient (α) and optical energy band (E g ) for the Se 55 Te 25 Ge 20 (GTS) alloy, Se 55 Te 25 Ge 20 +0.025% multiwalled carbon nano tubes (MWCNT) and Se 55 Te 25 Ge 20 +0.025 % bilayer graphene (GF) composites. Methods: To synthesize the materials direct melt-quenched technique was adopted. Materials microstructural and UV/ Visible optical absorption were performed from the Field Emission Scanning Electron Microscope and UV/ Visible optical spectrometer equipment’s. Results: The obtained experimental evidences are revealed that materials optical properties and microstructures slightly altered owing to incorporation of multi walled carbon nano tubes and bilayer graphene in Se 55 Te 25 Ge 20 regime. To correlate the inorganic- organic material interactions a schematic has also interpreted based on the bond formation in the solids. Conclusion: The experimental evidences have revealed the existence of MWCNT and GF in diffused form in GTS glassy configuration. The evidences have also revealed the diffused morphologies of the MWCNT and GF could not developed the specific structure within the complex configuration (although they have exhibited rather distinct morphologies), but they influenced the optical properties of the composite materials.


2013 ◽  
Author(s):  
Benoy Anand ◽  
Ramakrishna Podila ◽  
Apparao M. Rao ◽  
Reji Philip ◽  
S. Siva Sankara Sai

RSC Advances ◽  
2014 ◽  
Vol 4 (109) ◽  
pp. 63779-63783
Author(s):  
Szu-Chao Chen ◽  
Chih-Wei Chiu ◽  
Chung-Lin Wu ◽  
Ming-Fa Lin

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