Michael S. Shur

• Dr. Sc.
• Professor at Rensselaer Polytechnic Institute

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...

This paper presents an improved compact model for TeraFETs employing a nonlinear transmission line approach to describe the non-uniform carrier density oscillations and electron inertia effects in the TeraFET channels. By calculating the equivalent components for each segment of the channel—conductance, capacitance, and inductance—based on the volt...

Recent analysis revealed a great potential of diamond transistors for room-temperature THz sources and detectors. This paper reports on room-temperature sub-THz resonant oscillations of plasma waves in the p-diamond terahertz field-effect transistor (TeraFET). The instability mechanism in the hydrodynamic model predicts that the Dyakonov-Shur insta...

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 th...

An extreme bandgap Al0.64Ga0.36N quantum channel HEMT with Al0.87Ga0.13N top and back barriers, grown by MOCVD on a bulk AlN substrate, demonstrated a critical breakdown field of 11.37 MV/cm—higher than the 9.8 MV/cm expected for the channel’s Al0.64Ga0.36N material. We show that the fraction of this increase is due to the quantization of the 2D el...

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 th...

— An extreme bandgap Al0.64Ga0.36N quantum channel HEMT with Al0.87Ga0.13N top and back barriers grown by MOCVD over bulk AlN substrate demonstrated a critical breakdown field of 11.37 MV/cm, higher than 9.8 MV/cm expected for the channel Al0.64Ga0.36N material. We show that the fraction of this increase is due to the quantization of the 2D electro...

TeraFET arrays operating in plasmonic regimes could support the transition from 5G to 6G communication if the constituent TeraFETs operate in synchrony. Such arrays are plasmonic crystals supporting Bloch-like waves of electron density oscillations. The key issues are breaking symmetry and maintaining appropriate boundary conditions between the uni...

This paper presents an improved compact model for TeraFETs employing a nonlinear transmission line approach to describe the non-uniform carrier density oscillations and electron inertia effects in the TeraFET channels. By calculating the equivalent components for each segment of the channel-conductance, capacitance, and inductance-based on the volt...

Noting that the conventional collision-dominated electron transport perspective is only relevant when the length scale over which the transit occurs is greater than the electron’s mean free path, one can conceptually partition the electron transport “space” into collision-dominated and ballistic electron transport regimes. As the boundaries between...

We analyze the operation of the hot-electron FET bolometers with the graphene channels (GCs) and the gate barrier layers. Such bolometers use the thermionic emission of the hot electrons heated by incident-modulated THz radiation. The hot electrons transfer from the GC into the metal gate. As the THz detectors, these bolometers can operate at room...

In this paper, we analyze the modulation characteristics and the ultimate modulation frequency of the terahertz (THz) hot-electron FET bolometers with the graphene channels (GCs), metal gate (MG), and gate barrier layers (BLs) in a wide temperature range. Our results predict that the responsivity of GC-FET bolometers decreases with decreasing opera...

In this paper, 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...

Terahertz (THz) sensing technology enables 6G communication, detection of biological and chemical hazardous agents, cancer detection, monitoring of industrial processes and products, and detection of mines and explosives. THz sensors support security in buildings, airports, and other public spaces. They found important applications in radioastronom...

Definition The Pandemic Equation describes multiple pandemic waves and has been applied to describe the COVID-19 pandemic. Using the generalized approaches of solid-state physics, we derive the Pandemic Equation, which accounts for the effects of pandemic mitigation measures and multiple pandemic waves. The Pandemic Equation uses slow and fast time...

We analyze the generation of the terahertz (THz) radiation in photomixers using the interdigital graphene micro-nanoribbon (GMNR) array excited by modulated light or ultrashort radiation pulses. Replacing the standard metal electrodes by the GMNR array enables in the twofold advantages: an increase in the carrier generation efficiency due to the GM...

The terahertz (THz) plasmonic instability in the lateral graphene structure (LGS) with the n + ‐i‐n‐i‐n + junction in its graphene channel (GC) is analyzed. The i‐regions in the LGS n + ‐i‐n‐i‐n + GC plays the role of the transit spaces of the electrons emitted from the n + ‐regions (the emitters) and collected by the gated n‐region (collector) and...

We report on sub-terahertz plasmonic wave generation in the 2DEG channel of diamond TeraFET when biased by a DC current at the drain. Our numerical results demonstrated that p-diamond can support resonant oscillation of 300 GHz at room temperature, allowing it to function as a sub-THz emitter. We investigated the impact of different channel lengths...

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 GNR structures are associated with the electron and hole inductances and the lateral inter-GNR capacitance. A relatively low inter-GNR capacitance en...

High thermal conductivity and a high breakdown field make diamond a promising candidate for high-power and high-temperature semiconductor devices. Diamond also has a higher radiation hardness than silicon. Recent studies show that diamond has exceptionally large electron and hole momentum relaxation times, facilitating compact THz and sub-THz plasm...

Field effect transistors (FETs) in plasmonic regimes of operation could detect terahertz (THz) radiation and operate as THz interferometers, spectrometers, frequency-to-digital converters and THz modulators and sources. We report on the development of compact models for Si MOS (Metal-Oxide-semiconductor) and heterostructure-based plasmonic FETs (or...

A shorter switching time is one of the key advantages of GaN power devices over Si IGBTs. [1] In this paper, we report on the simulation of GaN power transistor switching and investigate the effect on the switching time novel design approaches ranging from the gate edge engineering (beyond just using field plates [2] for optimizing the voltage dist...

A shorter switching time and smaller conduction and switching losses are the key advantages of GaN power devices over Si technology. Further improvements of GaN HEMT technology will require new design approaches including SiC and even, possibly, diamond substrates, gate and drain edge engineering (beyond just using field plates) for optimizing the...

Within the framework of an electron transport regime classification scheme, we aim to explore the boundaries that occur between the ballistic, collision-dominated, space-charge injection, and non-space-charge injection electron transport regimes that are experienced by an electron within a semiconducting device, mapping out where these different el...

The rapid development of computer-aided design tools, such as MATLAB or Octave, or Mathematica enabled students to solve many complicated problems focusing less on underlying STEM-related concepts that are interdisciplinary. Therefore, it is important to demonstrate how it could be done using specific examples that could be linked to different subj...

Ever since the proposal and demonstration of quantum dots in 1980 by Drs. A. Efros, Al. Efros and A. Ekimov, the relentless progress of nanotechnology has been unstoppable. And nowhere this progress is more evident than in the Si Very Large Scale Integrated Circuits (VLSI) and Thin Film Transistor (TFT) technologies. The minimum feature size of the...

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...

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 oper...

We show that a periodic multi-grated-gate structure can be applied to THz plasmonic FETs (TeraFETs) to improve the THz detection sensitivity. The introduction of spatial non-uniformity by separated gate sections creates regions with distinct carrier concentrations and velocities, giving rise to harmonic behaviors. The resulting frequency spectrum o...

Previously, we showed within a sub-micron fin shape heterojunction, as current density increases, the non-radiative Auger recombination saturates mediated by the extension of the depletion region into the fin, resulting in a droop-free behavior. Here, we investigate the dependence of the fin aspect ratio (height to width ratio) on external quantum...

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 operat...

We developed a theory of collective plasma oscillations in a dc current-biased field effect transistor with an interdigitated dual grating gate and demonstrated a new mechanism of electron plasma instability in this structure. The instability in the plasmonic crystal formed in the transistor channel develops due to conversion of the kinetic energy...

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 $$_x$$ x P $$_{1-x}$$ 1 - x ) gate barrier layer. The operation of the GC-FET detectors is associated with the carrier heating in the GC by the THz el...

We analyze the operation of terahertz (THz) bolometric detectors based on field-effect transistor (FET) structures with graphene channels (GCs) and black-phosphorus and black-arsenic gate barrier layers (BLs). Such GC FETs use two-dimensional electron gas (2DEG) heating by the incident THz radiation leading to the thermionic emission of hot electro...

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 th...

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. The operation of these GC-FETs is associated with the heating of the two-dimensional electron gas in the GC by impingi...

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 res...

We developed a theory of collective plasma oscillations in a dc current-biased field effect transistor with interdigitated dual grating gate and demonstrated a new mechanism of electron plasma instability in this structure. The instability in the plasmonic crystal formed in the transistor channel develops due to conversion of the kinetic energy car...

Novel metal oxide materials such as InGaZnO (IGZO), ZnO, SnO, and In2O3 and improved fabrication processes dramatically enhanced the achieved and projected thin film transistor (TFT) performance. The recorded values of the effective field-effect mobility of metal oxide TFT (MOTFT) materials have approached 150 cm2/Vs. We report on an improved compa...

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 im...

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 elec...

We show that a periodic multi-grated-gate structure can be applied to THz plasmonic FETs (TeraFETs) to improve the THz detection sensitivity. The introduction of spatial non-uniformity by separated gate sections creates regions with distinct carrier concentrations and velocities, giving rise to harmonic behaviors. The resulting frequency spectrum o...

We report on the numerical and theoretical results of sub-THz and THz detection by a current-driven InGaAs/GaAs plasmonic field-effect transistor (TeraFET). New equations are developed to account for the channel length dependence of the drain voltage and saturation current. Numerical simulation results demonstrate that the effect of drain bias curr...

The Zener–Klein (ZK) interband tunneling in graphene layers (GLs) with the lateral n-i-n and p-i-n junctions results in the specific characteristics that can be used for the rectification, detection, amplification, and generation of the terahertz (THz) signals. The transit-time delay of the tunneling electrons and holes in the depletion regions lea...

Some of the best high-temperature commercial devices are now GaN field-effect transistors (FETs) on silicon substrates. However, these devices cannot meet requirements for space applications requiring high radiation hardness and for operations at temperatures as high as 600 o C. High temperature and radiation hard applications stimulated interest i...

Novel Thin-film-transistor (TFT) TFT materials such as ZnO, InGaZnO, AMO-CNT, and organic materials dramatically improved the achieved and projected TFT performance. The low field mobility of oxide materials has reached values comparable to those for short-channel Si CMOS. The effects related to electron inertia and electron density oscillations in...

Ultra-wide bandgap semiconductors - boron nitride, diamond, gallium oxide, and AlN - have a potential for high-temperature and radiation hard applications. These materials have a high breakdown field and large atom displacement energy correlated with a higher radiation hardness. Some of these materials, especially diamond, have a high thermal condu...

Novel materials such as ZnO, InGaZnO, AMO-CNT, and organic materials and improved fabrication processes dramatically enhanced the achieved and projected thin film transistor (TFT) performance. The effective field-effect mobility of metal oxide TFT materials has reached values comparable to those for short-channel Si CMOS. We report on an improved c...

We report on the numerical and theoretical results of sub-THz and THz detection by a current-driven InGaAs/GaAs plasmonic Field-Effect Transistor (TeraFET). New equations are developed to account for the channel length dependence of the drain voltage and saturation current. Numerical simulation results demonstrate that the effect of drain bias curr...

We show that resonant plasmonic detection dramatically increases the sensitivity of the terahertz detectors based on a gated graphene p-i-n (GPIN) field-effect transistor (FET) structure. In the proposed device, the gated p and n regions serve as the hole and electron reservoirs and the terahertz resonant plasma cavities. The current-voltage (I-V)...

We study how electrons, initially in thermal equilibrium, drift under the action of an applied electric field within bulk wurtzite zinc oxide. In particular, within the framework of a transient Monte Carlo analysis of the electron transport that occurs within this material, we determine the applied electric field strength that ensures the minimum t...

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 b...

Electrons and holes in graphene behave as relativistic charged massless Dirac fermions due to the graphene unique gapless electronic band structure with a linear dispersion law. Dirac plasmons - the quanta of the plasma oscillation of the Dirac electrons - can dramatically enhance the interaction of terahertz (THz) photons with graphene. We have pr...

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 rectifi...

Circularly polarized electromagnetic wave impinging on a conducting ring with a two-dimensional electron channel generates a circulating DC plasmonic current resulting in an inverse Faraday effect in nanorings. We show that a large ring with periodically modulated width on a nanoscale, smaller or comparable with the plasmonic mean free path, suppor...

We examine zinc-blende boron nitride’s low-field electron transport response. In particular, within the framework of a relaxation-time approximation analysis, we probe how the individual scattering processes contribute to the total electron drift mobility. The scattering processes considered include the ionized impurity, polar optical phonon, acous...

Drawing upon a collection of electron transport results, coupled with a variety of other material parameters, we set expectations on the upper limits to device performance of zinc blende boron-nitride-based electron devices. We examine how the device performance varies with the device length-scale, noting that a diversity of physical regimes are ex...

We analyze the response of lateral n ⁺ -i-n-n ⁺ graphene field-effect transistors (GFETs) to terahertz (THz) radiation. The nonlinearity due to the Coulomb drag of quasi-equilibrium carriers by injected ballistic carriers accompanied by plasmonic oscillations in a GFET channel enables a resonantly strong response. This effect can be used for effect...

We present an update of the Rensselaer Polytechnic Institute (RPI) thin-film transistor (TFT) compact model. The updated model implemented in Simulation Program with Integrated Circuit Emphasis (SPICE) accounts for the gate voltage-dependent channel layer thickness, enables the accurate description of the direct current (DC) characteristics, and us...

This paper reviews recent advances in the research and development of graphene-based plasmonic metamaterials for terahertz (THz) laser transistors. The authors’ theoretical discovery on THz laser transistors in 2007 was realized as a distributed-feedback dual-gate graphene-channel field-effect transistor (DFB-DG-GFET) in 2018, demonstrating ∼0.1 µW...

We use a linear approximation for the threshold voltage dependence on the body bias to derive the equation for the equivalent output resistance of the “extrinsic” MOSFET in the saturation regime. Previously we derived an equation for the equivalent output resistance of the “extrinsic” MOSFET in the saturation regime, that is based on the “intrinsic...

Ballistic Electrons The Coulomb drag effect in lateral n⁺–i–n–n⁺ graphene diode/transistor structures with ballistic injection of graphene Dirac fermions makes it possible to strongly modify the current-voltage characteristics to produce “gain” in the terahertz frequency range, leading to voltage- and current-driven switches, frequency multipliers,...

We evaluate the influence of Coulomb drag of electrons and holes in gated n and p regions caused by ballistic electrons and holes generated in a depleted i region due to interband tunneling on the current-voltage characteristics and impedance of p+-p-i-n-n+ graphene tunneling transistor structures (GTTSs). This drag leads to current amplification i...

Ever increasing demands of data traffic makes the transition to 6G communications in the 300 GHz band inevitable. Short-channel field-effect transistors (FETs) have demonstrated excellent potential for detection and generation of terahertz (THz) and sub-THz radiation. Such transistors (often referred to as TeraFETs) include short-channel silicon co...

We report on the effect of forward current stress on the low frequency noise in the 4H-SiC rectifier p +-n diodes rated at 20 and 10 kV. The 4H-SiC diodes with 20 kV blocking voltage were the most sensitive to the forward current stress. Even the stress by the current density j =13 A/ cm 2 for 30 min led to a noticeable increase in the forward volt...