Photovoltage Oscillations in Encapsulated Graphene

Mapping Intimacies ◽

10.21203/rs.3.rs-1241571/v1 ◽

2022 ◽

Author(s):

Jesús Iñarrea ◽

Gloria Platero

Keyword(s):

Boron Nitride ◽

Terahertz Radiation ◽

Gate Voltage ◽

Hexagonal Boron Nitride ◽

Monolayer Graphene ◽

Dirac Fermions ◽

Positive Voltage ◽

Carrier Effective Mass ◽

Electron Orbit ◽

Orbit Model

Abstract We theoretically analyze the rise of photovoltage oscillations in hexagonal boron-nitride (h-BN) encapsulated monolayer graphene (h-BN/graphene/h-BN) when irradiated with terahertz radiation. We use an extension of the radiation-driven electron orbit model, successfully applied to study the oscillations obtained in irradiated magnetotransport of GaAs/AlGaAs heterostructures. The extension takes mainly into account that now the carriers are massive Dirac fermions. Our simulations reveal that the photovoltage in these graphene systems presents important oscillations similar to the ones of irradiated magnetoresistance in semiconductor platforms but in the terahertz range. We also obtain that these oscillations are clearly affected by the voltages applied to the sandwiched graphene: a vertical gate voltage between the two hBN layers and an external positive voltage applied to one of the sample sides. The former steers the carrier effective mass and the latter the photovoltage intensity and the oscillations amplitude. The frequency dependence of the photo-oscillations is also investigated.

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Терагерцовые дисперсия и усиление при стриминге электронов в графене при 300 K

Физика и техника полупроводников ◽

10.21883/ftp.2020.09.49827.19 ◽

2020 ◽

Vol 54 (9) ◽

pp. 888

Author(s):

А.А. Андронов ◽

В.И. Позднякова

Keyword(s):

Boron Nitride ◽

Electric Field ◽

Terahertz Radiation ◽

High Resistance ◽

Applied Voltage ◽

Momentum Space ◽

Hexagonal Boron Nitride ◽

Strong Electric Field ◽

Microwave Generator ◽

Time Frequency

Abstract We interpret the recent observations of Otsuji’s team (Sendai) on switching from absorption to amplification at a temperature of T = 300 K during the passage of terahertz radiation through hexagonal boron nitride–graphene sandwiches with multiple gates on the surface with an increase in the electric field in graphene. It is shown that these effects are related to dispersion and negative conductivity near the transit-time frequency of electrons in momentum space under streaming (anisotropic distribution) in graphene in a strong electric field. On the basis of these data, a universal tunable terahertz source is proposed, which has the form of a graphene-containing sandwich with a high-resistance silicon wafer (a cavity) with an applied voltage. This terahertz cavity is a complete analog of the microwave generator implemented on an InP chip by Vorobev’s team (St. Petersburg).

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Screening effect of monolayer van der Waals crystals on surface deicing: a molecular simulation study

Physical Chemistry Chemical Physics ◽

10.1039/d0cp04656f ◽

2020 ◽

Vol 22 (47) ◽

pp. 27873-27881

Author(s):

Yue Wang ◽

Yufeng Guo ◽

Wanlin Guo

Keyword(s):

Boron Nitride ◽

Molecular Simulation ◽

Simulation Study ◽

Hexagonal Boron Nitride ◽

Van Der Waals ◽

Monolayer Graphene ◽

Screening Effect ◽

Nitride Coatings

Significant screening effect of monolayer graphene and hexagonal boron nitride coatings on surface deicing of superhydrophilic and superhydrophobic crystals.

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Gate voltage induced topological phase transition in hexagonal boron-nitride bilayers

Applied Physics Letters ◽

10.1063/1.4775689 ◽

2013 ◽

Vol 102 (2) ◽

pp. 023104 ◽

Cited By ~ 9

Author(s):

Xuechao Zhai ◽

Guojun Jin

Keyword(s):

Phase Transition ◽

Boron Nitride ◽

Gate Voltage ◽

Hexagonal Boron Nitride ◽

Topological Phase ◽

Topological Phase Transition

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Localization to delocalization probed by magnetotransport of hBN/graphene/hBN stacks in the ultra-clean regime

Scientific Reports ◽

10.1038/s41598-021-98266-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Takuya Iwasaki ◽

Satoshi Moriyama ◽

Nurul Fariha Ahmad ◽

Katsuyoshi Komatsu ◽

Kenji Watanabe ◽

...

Keyword(s):

Elastic Scattering ◽

Boron Nitride ◽

High Temperatures ◽

Low Temperatures ◽

Dirac Point ◽

Hexagonal Boron Nitride ◽

Monolayer Graphene ◽

Scattering Mechanism ◽

High Quality ◽

Dirac Materials

AbstractWe report on magnetotransport in a high-quality graphene device, which is based on monolayer graphene (Gr) encapsulated by hexagonal boron nitride (hBN) layers, i.e., hBN/Gr/hBN stacks. In the vicinity of the Dirac point, a negative magnetoconductance is observed for high temperatures > ~ 40 K, whereas it becomes positive for low temperatures ≤ ~ 40 K, which implies an interplay of quantum interferences in Dirac materials. The elastic scattering mechanism in hBN/Gr/hBN stacks contrasts with that of conventional graphene on SiO2, and our ultra-clean graphene device shows nonzero magnetoconductance for high temperatures of up to 300 K.

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Energy Band Gap Modification of Graphene Deposited on a Multilayer Hexagonal Boron Nitride Substrate

MRS Proceedings ◽

10.1557/opl.2012.347 ◽

2012 ◽

Vol 1407 ◽

Author(s):

Celal Yelgel ◽

Gyaneshwar P. Srivastava

Keyword(s):

Boron Nitride ◽

Band Gap ◽

Energy Band ◽

Density Functional ◽

Hexagonal Boron Nitride ◽

Monolayer Graphene ◽

Stable Configuration ◽

Equilibrium Geometry ◽

Energy Band Gap ◽

Electron Speed

ABSTRACTThe equilibrium geometry and electronic structure of graphene deposited on a multilayer hexagonal boron nitride (h-BN) substrate has been investigated using the density functional and pseudopotential theories. We found that the energy band gap for the interface between a monolayer graphene (MLG) and a monolayer BN (MLBN) lies between 47 and 62 meV, depending on the relative orientations of the layers. In the most energetically stable configuration the binding energy is found to be approximately 40 meV per C atom. Slightly away from the Dirac point, the dispersion curve is linear, with the electron speed almost identical to that for isolated graphene. The dispersion relation becomes reasonably quadratic for the interface between MLG and 4-layer-BN, with a relative effective mass of 0.0047. While the MLG/MLBN superlattice is metallic, the thinnest armchair nanoribbon of MLG/MLBN interface is semiconducting with a gap of 1.84 eV.

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