Simulations of Graphene Base Transistors With Improved Graphene Interface Model

Lecce, Valerio Di; Gnudi, A.; Gnani, Elena; Reggiani, Susanna; Baccarani, G.

doi:10.1109/led.2015.2452214

Cited by 6 publications

(2 citation statements)

References 12 publications

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“…In spite of its interesting working principle, the practical implementation of this device concept has been hindered for a long time by the difficulty of fabricating a high-quality ultrathin base layer using conventional growth processes, which typically suffer of increased interface roughness and degraded transport properties for very thin (<5 nm) conducting films. Recently, the appearance of two-dimensional (2D) materials provided new solutions for the implementation of high-performance HETs. , In particular, graphene (Gr) has been proposed as an ideal base material, as it combines monatomic thickness, enabling ballistic electron transit in the transversal direction, with excellent in-plane transport properties (high mobility, from ∼10 3 up to ∼10 5 cm 2 V –1 s –1 , and very low resistivity). − Theoretical studies have predicted excellent high-frequency performances, with a cutoff frequency ( f T ) up to several terahertz, for Gr base HETs (GBHET). − …”

Section: Introductionmentioning

confidence: 99%

High-Performance Graphene/AlGaN/GaN Schottky Junctions for Hot Electron Transistors

Giannazzo

Greco

Schilirò

et al. 2019

ACS Appl. Electron. Mater.

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The electronic properties of the graphene (Gr) Schottky junction with an Al0.22Ga0.78N/GaN heterostructure on silicon have been investigated, both by experiment and with use of ab initio DFT calculations. A peculiarly high n-type doping (1.1 × 1013 cm–2), observed for Gr in contact with AlGaN, was explained by the combined effect of Fermi level pinning by AlGaN surface states and charge transfer. Spatially uniform current injection across the Gr/AlGaN/GaN heterojunction was revealed by nanoscale resolution conductive atomic force microscopy (CAFM) analyses. Furthermore, a Gr/AlGaN/GaN Schottky diode with excellent rectifying behavior has been demonstrated and used as the key building block for a hot electron transistor (HET) with a 10 nm Al2O3 base-collector barrier. Thanks to the highly efficient hot electron injection from the AlGaN/GaN emitter, this transistor exhibits high on-state current density (J C,ON ≈ 1 A/cm2), high on-state over off-state current density ratio (J C,ON/J C,OFF ≈ 106), and a common-base current gain α ≈ 0.15, solely limited by the high Al2O3 base–collector barrier. The excellent performances of the Gr/AlGaN/GaN Schottky junction represent an important step toward the development of a HET technology compatible with the state-of-the-art GaN high electron mobility transistors.

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Section: Introductionmentioning

confidence: 99%

High-Performance Graphene/AlGaN/GaN Schottky Junctions for Hot Electron Transistors

Giannazzo

Greco

Schilirò

et al. 2019

ACS Appl. Electron. Mater.

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“…As a result of the atomic thickness of graphene, the quantum capacitance cannot be treated simply as a capacitance in series or parallel connection to the tunneling barrier capacitance. Previous simulation works on graphene base hot electron transistors have taken into account the quantum capacitance of graphene in these vertical devices through the Dirac density of states , an analytical expression of the influence of the graphene quantum capacitance on the vertical tunneling process is still not readily available. Herein, we construct a new model to describe the capacitance–voltage characteristic of the graphene and the vdW gap in the vertical direction, which takes into account the atomic thickness and linear density of states of graphene, as well as the asymmetrical interfaces on the two sides of graphene.…”

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confidence: 99%

A Study of Vertical Transport through Graphene toward Control of Quantum Tunneling

et al. 2018

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Vertical integration of van der Waals (vdW) materials with atomic precision is an intriguing possibility brought forward by these two-dimensional (2D) materials. Essential to the design and analysis of these structures is a fundamental understanding of the vertical transport of charge carriers into and across vdW materials, yet little has been done in this area. In this report, we explore the important roles of single layer graphene in the vertical tunneling process as a tunneling barrier. Although a semimetal in the lateral lattice plane, graphene together with the vdW gap act as a tunneling barrier that is nearly transparent to the vertically tunneling electrons due to its atomic thickness and the transverse momenta mismatch between the injected electrons and the graphene band structure. This is accentuated using electron tunneling spectroscopy (ETS) showing a lack of features corresponding to the Dirac cone band structure. Meanwhile, the graphene acts as a lateral conductor through which the potential and charge distribution across the tunneling barrier can be tuned. These unique properties make graphene an excellent 2D atomic grid, transparent to charge carriers, and yet can control the carrier flux via the electrical potential. A new model on the quantum capacitance's effect on vertical tunneling is developed to further elucidate the role of graphene in modulating the tunneling process. This work may serve as a general guideline for the design and analysis of vdW vertical tunneling devices and heterostructures, as well as the study of electron/spin injection through and into vdW materials.

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Simulation of Graphene Base Transistors With Bilayer Tunnel Oxide Barrier: Model Calibration and Performance Projection

Lecce

Gnudi

Gnani

et al. 2016

IEEE Electron Device Lett.

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Simulations of Graphene Base Transistors With Improved Graphene Interface Model

Cited by 6 publications

References 12 publications

High-Performance Graphene/AlGaN/GaN Schottky Junctions for Hot Electron Transistors

High-Performance Graphene/AlGaN/GaN Schottky Junctions for Hot Electron Transistors

A Study of Vertical Transport through Graphene toward Control of Quantum Tunneling

Simulation of Graphene Base Transistors With Bilayer Tunnel Oxide Barrier: Model Calibration and Performance Projection

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