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We describe studies on the nanoscale transport dynamics of carriers in strained AlN/GaN/AlN quantum wells: an electron-hole bilayer charge system with large difference in transport properties between the two charge layers. From electronic…

Mesoscale and Nanoscale Physics · Physics 2017-08-17 H. Condori Quispe , S. M. Islam , S. Bader , A. Chanana , K. Lee , R. Chaudhuri , A. Nahata , H. G. Xing , D. Jena , B. Sensale-Rodriguez

The optical properties of graphene are made unique by the linear band structure and the vanishing density of states at the Dirac point. It has been proposed that even in the absence of a semiconducting bandgap, a relaxation bottleneck at…

Graphene-based terahertz (THz) devices have emerged as promising platforms for a variety of applications, leveraging graphene's unique optoelectronic properties. This review explores recent advancements in utilizing graphene in THz…

We present a numerical study on the intraband optical conductivity of hot carriers at quasi-equilibria in photoexcited graphene based on the semiclassical Boltzmann transport equations (BTE) with the aim of understanding the effects of…

Mesoscale and Nanoscale Physics · Physics 2021-02-24 Masatsugu Yamashita , Chiko Otani

We reveal that there exists a class of graphene structures (a sub-class of bilayer graphene nanoribbons) which has unusually strong optical response in the terahertz (THz) and far infrared (FIR) regime. The peak conductance of terahertz/FIR…

Mesoscale and Nanoscale Physics · Physics 2009-05-28 A. R. Wright , J. C. Cao , C. Zhang

We report on the effects of laser illumination on the electronic properties of bilayer graphene. By using Floquet theory combined with Green's functions we unveil the appeareance of laser-induced gaps not only at integer multiples of $\hbar…

Mesoscale and Nanoscale Physics · Physics 2013-01-16 E. Suárez Morell , L. E. F. Foa Torres

In the second-order response regime, the Hall voltage can be nonzero without breaking the time-reversal symmetry, as long as the system is noncentrosymmetric. There are multiple mechanisms with different scaling rules that contribute to the…

Mesoscale and Nanoscale Physics · Physics 2022-04-22 Junxi Duan , Yu Jian , Yang Gao , Huimin Peng , Jinrui Zhong , Qi Feng , Yugui Yao

A Drude-Boltzmann theory is used to calculate the transport properties of bilayer graphene. We find that for typical carrier densities accessible in graphene experiments, the dominant scattering mechanism is overscreened Coulomb impurities…

Mesoscale and Nanoscale Physics · Physics 2008-03-22 Shaffique Adam , S. Das Sarma

We present a theoretical study of the intrinsic plasmonic properties of twisted bilayer graphene (TBG) as a function of the twist angle $\theta$ (and other microscopic parameters such as temperature and filling factor). Our calculations,…

Mesoscale and Nanoscale Physics · Physics 2024-09-06 Lorenzo Cavicchi , Iacopo Torre , Pablo Jarillo-Herrero , Frank H. L. Koppens , Marco Polini

Optical pump-terahertz probe differential transmission measurements of as-prepared single layer graphene (AG)(unintentionally hole doped with Fermi energy $E_F$ at $\sim$180 meV), nitrogen doping compensated graphene (NDG) with $E_F$…

Materials Science · Physics 2015-06-22 Srabani Kar , Dipti R. Mohapatra , Eric Freysz , A. K. Sood

The scarcity of spectrum resources in current wireless communication systems has sparked enormous research interest in the terahertz (THz) frequency band. This band is characterized by fundamentally different propagation properties…

Signal Processing · Electrical Eng. & Systems 2020-04-17 Akram Shafie , Nan Yang , Zhuo Sun , Salman Durrani

We report a terahertz optical modulator consisting of randomly stacked trilayer graphene (TLG) deposited on an oxidized silicon substrate by means of THz- Time Domain Spectroscopy (THz-TDS). Here, the gate tuning of the Fermi level of the…

Materials Science · Physics 2017-01-31 Ioannis Chatzakis , Zhen Li , Alex Benderskii , Stephen B. Cronin

The higher order harmonic generation process in the nonperturbative regime at the interaction of coherent electromagnetic radiation with the AB-stacked bilayer graphene at high Fermi energies is considered. The applied coherent…

Mesoscale and Nanoscale Physics · Physics 2020-07-20 A. G. Ghazaryan , H. H. Matevosyan , Kh. V. Sedrakian

The efficient amplification and lasing of electromagnetic radiation at terahertz (THz) frequencies is a non-trivial task achieved mainly by quantum cascade laser configurations with limited tunability and narrowband functionality. There is…

Optics · Physics 2018-11-30 Tianjing Guo , Liang Zhu , Pai-Yen Chen , Christos Argyropoulos

We calculate the transport properties of multilayer graphene, considering the effect of multisubband scattering in a high density regime, where higher subbands are occupied by charge carriers. To calculate the conductivity of multilayer…

Mesoscale and Nanoscale Physics · Physics 2017-05-12 Seungchan Woo , E. H. Hwang , Hongki Min

We examine the unusual dispersion and attenuation of transverse electromagnetic waves in the few-THz regime on nanoscale graphene and copper transmission lines. Conventionally, such propagation has been considered to be highly dispersive,…

Optics · Physics 2020-02-13 S. Hossein Mousavi , Ian A. D. Williamson , Zheng Wang

In this paper, we analytically design a simple configuration of a broadband THz and polarization-insensitive absorber. The mentioned absorber consists of two layers of graphene disks, and the transmission line model is considered for the…

In this study, terahertz (THz) absorption and transmission of monolayer MoS$_{2}$ was calculated under different carrier concentrations. Results showed that the THz absorption of monolayer MoS$_{2}$ is very small even under high carrier…

Optics · Physics 2016-01-20 Xue-Yong Deng , Xin-Hua Deng , Fu-Hai Su , Nian-Hua Liu , Jiang-Tao Liu

The inhomogenous real-space electronic structure of gapless and gapped disordered bilayer graphene is calculated in the presence of quenched charge impurities. For gapped bilayer graphene we find that for current experimental conditions the…

Mesoscale and Nanoscale Physics · Physics 2015-03-19 E. Rossi , S. Das Sarma

Using terahertz time-domain spectroscopy, the real part of optical conductivity [$\sigma_{1}(\omega)$] of twisted bilayer graphene was obtained at different temperatures (10 -- 300 K) in the frequency range 0.3 -- 3 THz. On top of a…