arXiv subjects

M. Ryzhii

Publications and source records attributed to M. Ryzhii.

At least 19 recordsLinked to original sources

arXiv2025

Effect of doping on hot-carrier thermal breakdown in perforated graphene metasurfaces

We examine the robustness of the S-shaped current-voltage characteristics associated with hot-carrier-induced electrical breakdown in perforated graphene metasurfaces (PGMs) as a function of doping. The perforation of the graphene layer forms interdigital arrays of graphene microribbons (GMRs) interconnected by graphene nanoribbon (GNR) bridges. These GNR constrictions act as energy barriers for electrons and holes emitted from the GMRs and govern the inter-GMR thermionic current under an applied bias voltage. The doping and the voltage bias establish distinct electron and hole populations in adjacent GMRs. Peltier heating of these carriers within the GMRs increases their effective temperatures, thereby enhancing the inter-GMR current. The resulting positive feedback between carrier heating and current amplification can trigger an electrothermal breakdown, transforming a superlinear current-voltage dependence into an S-shaped characteristic exhibiting negative differential resistance. The degree of electron-hole asymmetry significantly influences this positive feedback and strongly modifies the overall current-voltage response. These results provide a framework for optimizing PGM-based devices employing GMR/GNR architectures, including voltage-controlled fast switches, incandescent emitters, and terahertz bolometric detectors.

cond-mat.mes-hall↗

arXiv2025

Thermal hot-carrier breakdown in metasurface structures based on coplanar arrays of graphene microribbons connected with wide-gap bridges

We analyze the thermal and electrical characteristics of the metasurface consisting of the coplanar interdigital array of the graphene microribbons (GMRs) connected by nanobridges (NBs). These nanobridges could be implemented using graphene nanoribbons (GNRs), single-wall semiconducting carbon nanotubes (CNTs), or black-arsenic-phosphorus (b-AsP) nanostructures. The bias voltage applied between neighboring GMRs indices electron and hole two-dimensional systems in the GMRs and induces thermionic currents flowing through connecting NBs. The resulting self-heating increases thermionic currents providing an effective positive feadback between the carrier effective temperature and the injected currents. This mechanism may lead to thermal breakdown enabling threshold behavior of current-voltage characteristics and resulting in the S-shape of these characteristics. The devices based on the GMR/GNR, GMR/CNT, and GMR/AsP metasurface structures can be used as fast voltage-controlled current switches, sensors, thermal terahertz and infrared sources, and other devices.

cond-mat.mes-hall↗

arXiv2025

Rectification and bolometric terahertz radiation detectors based on perforated graphene structures exhibiting plasmonic resonant response

We propose and evaluate the characteristics of the terahertz (THz) detectors based on perforated graphene layers (PGLs). The PGL structures constitute the interdigital in-plane arrays of the graphene microribbons (GMRs) connected by the sets of narrow constrictions, which form the graphene nanoribbon (GNR) bridges. The PGL detector operation is associated with the rectification and hot-carrier bolometric mechanisms. The excitation of plasmonic oscillations in the GMR-GNR arrays can reinforce these mechanisms. The room temperature PGL detector responsivity and detectivity are calculated as function of the radiation frequency and device structure parameters. The effects of the rectification and hot-carrier mechanisms are compared. The PGL THz detectors under consideration can exhibit highly competitive values of responsivity and detectivity.

cond-mat.mes-hall↗

arXiv2025

Hot-carrier thermal breakdown and S-type current-voltage characteristics in perforated graphene structures

We investigate the carrier transport characteristics of perforated graphene layer (PGL) composed of arrays of interdigital coplanar graphene microribbons (GMRs) connected by graphene nanoribbon (GNR) bridges. We analyze their operation at room-temperature. Under an applied bias voltage, two-dimensional electron and hole systems (2DES and 2DHS) form in adjacent GMRs. The terminal current in these PGL structures is primarily governed by thermionic transport across the GNR bridges. As electrons and holes traverse the GNRs, they induce heating in the 2DES and 2DHS, creating a positive feedback loop between carrier heating and thermionic emission. This phenomenon, characterized as hot-carrier thermal breakdown, can give rise to S-shaped inter-GMR current-voltage characteristics. These unique transport properties make PGLs promising candidates for fast, voltage-controlled room-temperature switches and electromagnetic radiation detectors.

cond-mat.mes-hall↗

arXiv2024

Detection of terahertz radiation using topological graphene micro-nanoribbon structures with transverse plasmonic resonant cavities

The lateral interdigital array of the graphene microribbons (GMRs) on the h-BN substrate connected by narrow graphene nanoribbon (GNR) bridges serves as an efficient detector of terahertz (THz) radiation. The detection is enabled by the nonlinear GNR elements providing the rectification of the THz signals. The excitation of plasmonic waves along the GMRs (transverse plasmonic oscillations) by impinging THz radiation can lead to a strong resonant amplification of the rectified signal current and substantial enhancement of the detector response. The GMR arrays with the GNR bridges s can be formed by the perforation of uniform graphene layers

cond-mat.mes-hall↗

arXiv2024

Dynamic characteristics of terahertz hot-electron graphene FET bolometers: effect of electron cooling in channel and at side contacts

We analyze the operation of the hot-electron FET bolometers with the graphene channels (GCs) and the gate barrier layers (BLs). Such bolometers use the thermionic emission of the hot electrons heated by incident modulated THz radiation. The hot electron transfer from the GC into the metal gate. As the THz detectors, these bolometers can operate at room temperature. We show that the response and ultimate modulation frequency of the GC-FET bolometers are determined by the efficiency of the hot-electron energy transfer to the lattice and the GC side contacts due to the 2DEG lateral thermal conductance. The dependences of these mechanisms on the band structure and geometrical parameters open the way for the GC-FET bolometers optimization, in particular, for the enhancement of the maximum modulation frequency.

cond-mat.mes-hall↗

arXiv2024

Terahertz plasmonic resonances in coplanar graphene nanoribbon structures

We analyze plasmonic oscillations in the coplanar graphene nanoribbon (GNR) structures induced by the applied terahertz (THz) signals and calculate the GNR impedance. The plasmonic oscillations in the CNR structures are associated with the electron and hole inductances and the lateral inter-CNR capacitance. A relatively low inter-GNR capacitance enables the resonant excitation of the THz plasmonic oscillations in the CNR structures with long GNRs. The GNR structures under consideration can be used in different THz devices as the resonant structures incorporated in THz detectors, THz sources using resonant-tunneling diodes, photomixers, and surface acoustic wave sensors.

cond-mat.mes-hall↗

arXiv2023

Phase- and angle-sensitive terahertz hot-electron bolometric plasmonic detectors based on FETs with graphene channel and composite h-BN/black-P/h-BN gate layer

We propose and analyze the terahertz (THz) bolometric vector detectors based on the graphene-channel field-effect transistors (GC-FET) with the black-P gate barrier layer or with the composite b-BN/black-P/b-BN gate layer. The phase difference between the signal received by the FET source and drain substantially affects the plasmonic resonances. This results in a resonant variation of the detector response on the incoming THz signal phase shift and the THz radiation angle of incidence.

cond-mat.mes-hall↗

arXiv2023

Micromechanical field-effect transistor terahertz detectors with optical interferometric readout

We investigate the response of the micromechanical field-effect transistors (MMFETs) to the impinging terahertz (THz) signals. The MMFET uses the microcantilevers MC as a mechanically floating gate and the movable mirror of the Michelson optical interferometer. The MC mechanical oscillations are transformed into optical signals and the MMFET operates as the detector of THz radiation with the optical output. The combination of the mechanical and plasmonic resonances in the MMFET with the optical amplification enables an effective THz detection.

physics.app-ph↗

arXiv2023

Terahertz bolometric detectors based on graphene field-effect transistors with the composite h-BN/black-P/h-BN gate layers using plasmonic resonances

We propose and analyze the performance of terahertz (THz) room-temperature bolometric detectors based on the graphene channel field-effect transistors (GC-FET). These detectors comprise the gate barrier layer (BL) composed of the lateral hexagonal-Boron Nitride black-Phosphorus/ hexagonal-Boron Nitride (h-BN/b-P/h-BN) structure. The main part of the GC is encapsulated in h-BN, whereas a short section of the GC is sandwiched between the b-P gate BL and the h-BN bottom layer. The b-P gate BL serves as the window for the electron thermionic current from the GC. The electron mobility in the GC section encapsulated in h-BN can be fairly large. This might enable a strong resonant plasmonic response of the GC-FET detectors despite relatively lower electron mobility in the GC section covered by the b-P window BL. The narrow b-P window diminishes the Peltier cooling and enhances the detector performance. The proposed device structure and its operation principle promote elevated values of the room-temperature GC-FET THz detector responsivity and other characteristics, especially at the plasmonic resonances.

cond-mat.mes-hall↗

arXiv2023

Hot-electron resonant terahertz bolometric detection in the graphene/black-AsP field-effect transistors with a floating gate

We evaluate the terahertz (THz) detectors based on field effect transistor (FET) with the graphene channel {GC} and a floating metal gate (MG) separated from the GC by a black-phosphorus (b-P) or black-arsenic (b-As) barrier layer (BL). The operation of these GC-FETs is associated with the heating of the two-dimensional electron gas in the GC by impinging THz radiation leading to thermionic emission of the hot electrons from the GC to the MG. This results in the variation of the floating gate potential, which affects the source-drain current. At the THz radiation frequencies close to the plasmonic resonance frequencies in the gated GC, the variation of the source-drain current and, hence, the detector responsivity can be resonantly large.

cond-mat.mes-hall↗

arXiv2023

Resonant plasmonic detection of terahertz radiation in field-effect transistors with the graphene channel and the black-As$_x$P$_{1-x}$ gate layer

We propose the terahertz (THz) detectors based on field-effect transistors (FETs) with the graphene channel (GC) and the black-Arsenic (b-As) black-Phosphorus (b-P), or black-Arsenic-Phosphorus (b-As$_x$P$_{1-x}$) gate barrier layer. The operation of the GC-FET detectors is associated with the carrier heating in the GC by the THz electric field resonantly excited by incoming radiation leading to an increase in the rectified current between the channel and the gate over the b-As$_x$P$_{1-x}$ energy barrier layer (BLs). The specific feature of the GC-FETs under consideration is relatively low energy BLs and the possibility to optimize the device characteristics by choosing the barriers containing a necessary number of the b-As$_x$P$_{1-x}$ atomic layers and a proper gate voltage. The excitation of the plasma oscillations in the GC-FETs leads to the resonant reinforcement of the carrier heating and the enhancement of the detector responsivity. The room temperature responsivity can exceed the values of $10^3$~A/W. The speed of the GC-FET detector's response to the modulated THz radiation is determined by the processes of carrier heating. As shown, the modulation frequency can be in the range of several GHz at room temperatures.

cond-mat.mes-hall↗

arXiv2023

Effect of electron thermal conductivity on resonant plasmonic detection in the metal/black-AsP/graphene FET terahertz hot-electron bolometers

We analyze the two-dimensional electron gas (2DEG) heating by the incident terahertz (THz) radiation in the field-effect transistor (FET) structures with the graphene channels (GCs) and the black-phosphorus and black-arsenic gate barrier layers (BLs). Such GC-FETs can operate as bolometric THz detectors using the thermionic emission of the hot electrons from the GC via the BL into the gate. Due to the excitation of plasmonic oscillations in the GC by the THz signals, the GC-FET detector response can be pronouncedly resonant, leading to elevated values of the detector responsivity. The lateral thermal conductivity of the 2DEG can markedly affect the GC-FET responsivity, in particular, its spectral characteristics. This effect should be considered for the optimization of the GC-FET detectors.

cond-mat.mes-hall↗

arXiv2022

Resonant plasmonic terahertz detection in gated graphene p-i-n field-effect structures enabled by the Zener-Klein tunneling nonlinearity

We propose and analyze the terahertz (THz) detectors based on a gated graphene p-i-n (GPIN) field-effect transistor (FET) structure. The reverse-biased i-region between the gates plays the role of the electrons and holes injectors exhibiting nonlinear $I-V$ characteristics due to the Zener-Klein tunneling. This region enables the THz signal rectification, which provides their detection. The gated regions serve as the electron and hole reservoirs and the THz resonant plasma cavities. The resonant excitation of the electron and hole plasmonic oscillations results in a substantial increase in the THz detector responsivity at the signal frequency close to the plasma frequency and its harmonics. Due to the specifics of the i-region AC conductance frequency dependence, associated with the transit-time effects, the GPIN-FET response at the frequency, corresponding to the excitation of a higher plasmonic mode, can be stronger than for the fundamental mode. The GPIN-FETs can exhibit fairly high responsivity at room temperatures. Lowering of the latter can result in its further enhancement due to weakening of the carrier momentum relaxation.

cond-mat.mes-hall↗

arXiv2022

Transit-time resonances enabling amplification and generation of terahertz radiation in periodic graphene p-i-n structures with the Zener-Klein interband tunneling

The Zener-Klein (ZK) interband tunneling in graphene layers (GLs) with the lateral n-i-n and p-i-n junctions results in the nonlinear I-V characteristics that can be used for the rectification and detection of the terahertz (THz) signals. The transit time delay of the tunneling electrons and holes in the depletion regions leads to the phase shift between the THz current and THz voltage causing the negative dynamic conductance in a certain frequency range and resulting in the so-called transit-time (TT) instability. The combination of the ZK tunneling and the TT negative dynamic conductance enables resonant THz detection and the amplification and generation of THz radiation. We propose and evaluate the THz devices based on periodic cascade GL p-i-n structures exhibiting the TT resonances (GPIN-TTDs). Such structures can serve as THz amplifiers and, being placed in a Fabri-Perot cavity, or coupled to a THz antenna or using a ring oscillator connection, as THz radiation sources.

cond-mat.mes-hall↗

arXiv2021

Ballistic injection terahertz plasma instability in graphene n+-i-n-n+ field-effect transistors and lateral diodes

We analyze the operation of the graphene n+-i-n-n+ field-effect transistors (GFETs) and lateral diodes (GLDs) with the injection of ballistic electrons into the n-region. The momentum transfer of the injected ballistic electrons could lead to an effective Coulomb drag of the quasi-equilibrium electrons in the n-region and the plasma instability in the GFETs and GLDs. The instability enables the generation of terahertz radiation. The obtained results can be used for the optimization of the structures under consideration for different devices, in particular, terahertz emitters.

cond-mat.mes-hall↗

arXiv2021

Effect of Coulomb carrier drag and terahertz plasma instability in p+-p-i-n-n+ graphene tunneling transistor structures

We evaluate the influence of the Coulomb drag of the electrons and holes in the gated n- and p-regions by the ballistic electrons and holes generated in the depleted i-region due to the interband tunneling on the current-voltage characteristics and impedance of the p+-p-i-n-n+ graphene tunneling transistor structures (GTTSs). The drag leads to a current amplification in the gated n- and p-regions and a positive feedback between the amplified dragged current and the injected tunneling current. A sufficiently strong drag can result in the negative real part of the GTTS impedance enabling the plasma instability and the self-excitation of the plasma oscillations in the terahertz (THz) frequency range. This effect might be used for the generation of the THz radiation.

cond-mat.mes-hall↗

arXiv2021

S-shaped current-voltage characteristics of n+-i-n-n+ graphene field-effect transistors due the Coulomb drag of quasi-equilibrium electrons by ballistic electrons

We demonstrate that the injection of the ballistic electrons into the two-dimensional electron plasma in lateral n$^+$-i-n-n$^+$ graphene field-effect transistors (G-FET) might lead to a substantial Coulomb drag of the quasi-equilibrium electrons due the violation of the Galilean and Lorentz invariance in the systems with a linear electron dispersion. This effect can result in the S-shaped current-voltage characteristics (IVs). The resulting negative differential conductivity enables the hysteresis effects and current filamentation that can be used for the implementation of voltage switching devices. Due to a strong nonlinearity of the IVs, the G-FETs can be used for an effective frequency multiplication and detection of terahertz radiation.

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