COOS: a wave-function based Schrödinger–Poisson solver for ballistic nanotube transistors

Claus, Martin; Mothes, Sven; Blawid, Stefan; Schröter, M.

doi:10.1007/s10825-014-0588-6

Cited by 39 publications

(17 citation statements)

References 42 publications

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“…The latter correspond to a self-consistent solution of the semiclassical Boltzmann transport equation (BTE) and the Poisson equation [6], [18]. Since the measured device behavior is expected to be dominated by SB-related effects, the latter are also incorporated in the device simulation by modeling the tunneling through the barrier with the WKB method [19], [20]. The channel of the simulated SB-CNTFET used for demonstration purposes in this work is 400 nm long, has a coaxial gate with a gateoxide thickness of 5 nm and a dielectric constant of 16.…”

Section: Model For Semiconducting Tubesmentioning

confidence: 99%

A Semiphysical Large-Signal Compact Carbon Nanotube FET Model for Analog RF Applications

Schröter

Haferlach

Pacheco‐Sanchez

et al. 2015

IEEE Trans. Electron Devices

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A compact large-signal model, called Compact Carbon Nanotube Model (CCAM), is presented that accurately describes the shape of DC and small-signal characteristics of fabricated carbon nano-tube FETs (CNTFETs). The new model consists of computationally efficient and smooth current and charge formulations. The model allows, for a given gate length, geometry scaling from single-finger single-tube to multifinger multitube transistors. Ambipolar transport, temperature dependence with self-heating, noise, and a simple trap model have also been included. The new model shows excellent agreement with the data from both the Boltzmann transport equation and measurements of Schottky-barrier CNTFETs and has been implemented in Verilog-A, making it widely available across circuit simulators. IndexTerms-Carbon nanotube field-effect transistor (CNTFET), compact transistor modeling, high-frequency circuit design.

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Section: Model For Semiconducting Tubesmentioning

confidence: 99%

A Semiphysical Large-Signal Compact Carbon Nanotube FET Model for Analog RF Applications

Schröter

Haferlach

Pacheco‐Sanchez

et al. 2015

IEEE Trans. Electron Devices

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“…Depending on the chosen device, the contact between the CNT and the metal can be either Ohmic or Schottky like. In any case, the SBs for electrons ( Φ n ) and holes ( Φ p ) change with strain and contribute to the thermionic conductance G th

G_{th} (ε) = \frac{4 e^{2}}{h} \sum_{n, p} {normale}^{- \frac{{italicΦ}_{n, p} (ε)}{k_{normalB} T}} \sim G_{th} (0) \cdot [e^{- α β ε} + e^{- false(1 - α false) β ε}]

where e is the elementary charge, h is Planck's constant, k B is Boltzmann's constant, and T is temperature. The condition

{italicΦ}_{p} + {italicΦ}_{n} = E_{normalG}

is constrained.…”

Section: Cnt Strain Sensor Descriptionmentioning

confidence: 99%

Carbon Nanotubes for Mechanical Sensor Applications

Wagner

Blaudeck

Meszmer

et al. 2019

Physica Status Solidi (a)

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Herein, the evolution of carbon nanotubes (CNTs) as functional material in nano‐ and microelectromechanical systems (N/MEMS) is featured. Introducing material morphologies for the CNTs in a homologue series (single CNTs—bundles, fibers, yarns—networks and thin films), different concepts for mechanical sensors based on the intrinsic and extrinsic properties of the CNT materials are introduced (piezoresistive effect, strain‐induced band bending, charge tunneling). In a rigorous theoretical treatment, the limits of the achievable sensor performance (i.e., gauge factor) are derived and discussed in the context of applications. A careful literature survey shows that highest sensitivity is reached for devices exploiting the intrinsic transport properties of single CNTs. For reliability tests of such sensor systems made from nanomaterials and classical MEMS, the specimen‐centered approach (SCA) is introduced to give viable insights into the structure property relationships and failure modes of CNT mechanical sensors. CNT actuation occurs on the macro‐, micro‐, and nanoscales via atomic force microscopy, electrostatic gating, integration in N/MEMS systems, or through substrate bending.

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“…The first interface can be influenced by several parameters such as contact geometry, contact length [7], the material used for the fabrication [8], and any interfacial layer that may be present between the metal and the nanotube. At the second interface, a change of the electronic structure of the metalcoated tube portion due to the interaction with the metal induces a potential step (barrier) [9], [10], [11]. An important contribution to the height of the potential step is the Schottky barrier height φ SB which is defined as the difference between the Fermi level and the value of conduction band of the CNT at the interface between the metal coated and uncoated tube portion.…”

Section: The Contact Resistance In Cntfetsmentioning

confidence: 99%

“…This has been obtained by fitting a numerical model to the experimental data which does not include the contribution of R q . The latter has been validated in [24] where the same device has been modeled with a Schrödinger-Poisson solver assuming ballistic transport, as in [23], and in which the contribution of R q is not included. The electrical characteristics of the device in [23] have been matched by the results obtained in [24].…”

Section: Measurementsmentioning

confidence: 99%

“…The latter has been validated in [24] where the same device has been modeled with a Schrödinger-Poisson solver assuming ballistic transport, as in [23], and in which the contribution of R q is not included. The electrical characteristics of the device in [23] have been matched by the results obtained in [24]. YFM 2 has been applied to the experimental data taken from [23] in the bias region from…”

Section: Measurementsmentioning

confidence: 99%

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Contact resistance extraction methods for short- and long-channel carbon nanotube field-effect transistors

Pacheco‐Sanchez

Claus

Mothes

et al. 2016

Solid-State Electronics

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Three different methods for the extraction of the contact resistance based on both the well-known transfer length method (TLM) and two variants of the Y-function method have been applied to simulation and experimental data of short-and long-channel CNTFETs. While for TLM special CNT test structures are mandatory, standard electrical device characteristics are sufficient for the Y-function methods. The methods have been applied to CNTFETs with low and high channel resistance. It turned out that the standard Y-function method fails to deliver the correct contact resistance in case of a relatively high channel resistance compared to the contact resistances. A physics-based validation is also given for the application of these methods based on applying traditional Si MOSFET theory to quasi-ballistic CNTFETs.

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COOS: a wave-function based Schrödinger–Poisson solver for ballistic nanotube transistors

Cited by 39 publications

References 42 publications

A Semiphysical Large-Signal Compact Carbon Nanotube FET Model for Analog RF Applications

A Semiphysical Large-Signal Compact Carbon Nanotube FET Model for Analog RF Applications

Carbon Nanotubes for Mechanical Sensor Applications

Contact resistance extraction methods for short- and long-channel carbon nanotube field-effect transistors

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