Temperature-Dependent Band Gap in Two-Dimensional Perovskites: Thermal Expansion Interaction and Electron–Phonon Interaction

2019 ◽  
Vol 10 (10) ◽  
pp. 2546-2553 ◽  
Author(s):  
Shuai Wang ◽  
Jiaqi Ma ◽  
Wancai Li ◽  
Jun Wang ◽  
Haizhen Wang ◽  
...  
2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Mingming Yang ◽  
Longlong Wang ◽  
Xiaofen Qiao ◽  
Yi Liu ◽  
Yufan Liu ◽  
...  

Abstract The defects into the hexagonal network of a sp2-hybridized carbon atom have been demonstrated to have a significant influence on intrinsic properties of graphene systems. In this paper, we presented a study of temperature-dependent Raman spectra of G peak and D’ band at low temperatures from 78 to 318 K in defective monolayer to few-layer graphene induced by ion C+ bombardment under the determination of vacancy uniformity. Defects lead to the increase of the negative temperature coefficient of G peak, with a value almost identical to that of D’ band. However, the variation of frequency and linewidth of G peak with layer number is contrary to D’ band. It derives from the related electron-phonon interaction in G and D’ phonon in the disorder-induced Raman scattering process. Our results are helpful to understand the mechanism of temperature-dependent phonons in graphene-based materials and provide valuable information on thermal properties of defects for the application of graphene-based devices.


1999 ◽  
Vol 60 (14) ◽  
pp. 10442-10446 ◽  
Author(s):  
M. Mierzejewski ◽  
J. Zieliński ◽  
P. Entel

2021 ◽  
Vol 257 ◽  
pp. 123792
Author(s):  
Aanchal Sati ◽  
Anil Kumar ◽  
Vikash Mishra ◽  
Kamal Warshi ◽  
Preeti Pokhriyal ◽  
...  

Nanophotonics ◽  
2015 ◽  
Vol 4 (1) ◽  
pp. 115-127 ◽  
Author(s):  
Hugen Yan

AbstractLayered materials, such as graphene, transition metal dichacogenides and black phosphorus have attracted lots of attention recently. They are emerging novel materials in electronics and photonics, with tremendous potential in revolutionizing the traditional electronics and photonics industry. Marrying layered material to the nanophotonics is being proved fruitful. With the recent emphasis and development of metasurfaces in nanophotonics, atomically thin materials can find their unique position and strength in this field. In this article, I will focus on one specific two dimensional material: bilayer graphene. Basic physics will be reviewed, such as band-gap opening, electron-phonon interaction, phonon-plasmon interaction and Fano resonances in the optical response. Moreover, I will review the application of bilayer graphene as a sensitive and fast photodetector. An outlook will be given in the final part of the paper.


2020 ◽  
Vol 90 (3) ◽  
pp. 427
Author(s):  
Н.Н. Нифтиев

The spectral distribution of photoconductivity and the temperature dependence of the photocurrent of monocrystals MnGaInS4 are studied. The intrinsic and extrinsic photoconductivities are revealed in the spectrum of photoconductivity. The wavelength range of 0.640–0.760 μm is shown when manganese deficiency in crystals appears and is due to an acceptor defect. The temperature dependence of the band gap in the monocrystals MnGaInS4 is related to the electron – phonon interaction. In the studied temperatures, increase in the photocurrent is associated with the thermal depletion of the attachment levels. The activation energy of the attachment levels is estimated.


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