Name: Yousefi Reza
Department: Engineering
Faculty: Power
Academic Rank: Associate Professor
Email: r . y o u s e f i @ i a u n o u r . a c . i r

Studies

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Journal Articles

Title
Authors
Publication Date
A New Binary Multi-layer Diffraction Grating
Abbas Zarifkar, Reza Yousefi
10/1/2008
Conference
Journal
International Journal of Computer Science and Network Security
Volume
8
Issue
6
Pages
262-265
Publisher
Description
Modeling of Ballistic Carbon Nanotube Transistors by Neural Space Mapping
R Yousefi, K Saghafi
12/20/2008
Conference
Computer and Electrical Engineering, 2008. ICCEE 2008. International Conference on
Journal
Volume
Issue
Pages
165-168
Publisher
IEEE
Description
Neural network model for ballistic carbon nanotube transistors
R Yousefi, K Saghafi, MK Moravvej-Farshi
1/3/2010
Conference
Nanoelectronics Conference (INEC), 2010 3rd International
Journal
Volume
Issue
Pages
183-184
Publisher
IEEE
Description
Numerical study of lightly doped drain and source carbon nanotube field effect transistors
Reza Yousefi, Kamyar Saghafi, Mohammad Kazem Moravvej-Farshi
4/14/2010
Conference
Journal
Electron Devices, IEEE Transactions on
Volume
57
Issue
4
Pages
765-771
Publisher
IEEE
Description
ترانزیستور نانولوله کربنی با گیت گسترش یافته
رضا یوسفی، کامیار ثقفی و محمد کاظم مروج فرشی
5/26/2010
Conference
هجدهمین کنفرانس بین المللی مهندسی برق ایران
Journal
Volume
Issue
Pages
1203-1207
Publisher
Description
Application of neural space mapping for modeling ballistic carbon nanotube transistors
REZA Yousefi, MK Moravvej-Farshi, K Saghafi
10/1/2010
Conference
Journal
Iranian Journal of Electrical and Electronic Engineering
Volume
6
Issue
2
Pages
70-76
Publisher
Description
Effect of uniaxial strain on the subthreshold swing of ballistic carbon nanotube FETs
Reza Yousefi
8/31/2011
Conference
Journal
Physica E: Low-dimensional Systems and Nanostructures
Volume
43
Issue
10
Pages
1896-1901
Publisher
Elsevier
Description
A model for carbon nanotube FETs in the ballistic limit
R Yousefi, M Shabani
11/30/2011
Conference
Journal
Microelectronics Journal
Volume
42
Issue
11
Pages
1299-1304
Publisher
Elsevier
Description
THE EFFECT OF CARBON NANOTUBE CHIRALITY ON THE PERFORMANCE OF THE STRAINED TUNNELING CARBON NANOTUBE FETs
Reza Yousefi
1/30/2012
Conference
Journal
Modern Physics Letters B
Volume
26
Issue
03
Pages
1150019
Publisher
World Scientific Publishing Company
Description
Numerical Study of Ohmic-Schottky Carbon Nanotube Field Effect Transistor
Reza Yousefi, Seyed Saleh Ghoreyshi
6/20/2012
Conference
Journal
Modern Physics Letters B
Volume
26
Issue
15
Pages
1250096
Publisher
World Scientific Publishing Company
Description
A COMPUTATIONAL STUDY OF STRAIN EFFECTS IN THE BAND-TO-BAND-TUNNELING CARBON NANOTUBE FIELD-EFFECT TRANSISTORS
Reza Yousefi, Seyyed Saleh Ghoreishi
11/20/2012
Conference
Journal
International Journal of Modern Physics B
Volume
26
Issue
29
Pages
1250155
Publisher
World Scientific Publishing Company
Description
A computational study on electrical characteristics of a novel band-to-band tunneling graphene nanoribbon FET
R Yousefi, M Shabani, M Arjmandi, SS Ghoreishi
7/31/2013
Conference
Journal
Superlattices and Microstructures
Volume
60
Issue
Pages
169-178
Publisher
Academic Press
Description
Graphene nanoribbon tunnel field effect transistor with lightly doped drain: Numerical simulations
Seyed Saleh Ghoreishi, Kamyar Saghafi, Reza Yousefi, Mohammad Kazem Moravvej-Farshi
11/30/2014
Conference
Journal
Superlattices and Microstructures
Volume
Issue
Pages
245-256
Publisher
Academic Press
Description
A mathematical space mapping model for ballistic carbon nanotube field-effect transistors
Farnousha Emamifar and Reza Yousefi
11/11/2015
Conference
Journal
International nano letters
Volume
Issue
Pages
Publisher
Springer
Description
Hetero-junction carbon nanotube FET with lightly doped drain and source regions
Reza Yousefi and Leila Doorzad
1/8/2016
Conference
Journal
International Journal of Modern Physics B
Volume
30
Issue
Pages
1650005-1:1650005-9
Publisher
World Scientific Publishing Company
Description
In this paper, a new structure was introduced for carbon nanotube (CNT) MOSFET transistors. The proposed structure was composed of two different nanotubes for the source/drain and channel regions. Electrical characteristics of this structure were investigated using nonequilibrium Green’s function approach. Results of the simulations demonstrated that the proposed hetero-structure had almost the same ON-current and much less OFF-current and as a result higher ION/IOFF ratio than the conventional homo-structure. Results of the comparison between switching behavior in equal ION/IOFF ratio showed that, although the proposed structure had longer delay, its power dissipation for every switching event was less than that of the conventional structure. A further comparison of the switching characteristic in equal ON-current values showed that the proposed structure enjoys from shorter delay and also consumes less power-delay product (PDP) when compared to the LDDS structure.
Effect of uniaxial strain on electrical properties of CNT-based junctionless field-effect transistor: Numerical study
Parisa Pourian, Reza Yousefi, Seyed Saleh Ghoreishi
3/14/2016
Conference
Journal
Superlattices and Microstructures
Volume
93
Issue
Pages
92-100
Publisher
Elsevier
Description
Numerical studies on junctionless carbon nanotube field-effect transistors (JL-CNTFETs) have indicated that these devices produce more ON current than silicon junctionless transistors in comparable dimensions. Nevertheless, due to the smaller bandgap and quantum confinement effects, they provide weaker results in the OFF state. Since the change of energy bandgap is one of the effects of applying uniaxial strain on CNTs, in this paper, using non-equilibrium Green’s function method (NEGF), the effects of applying strain on electrical characteristics of JL-CNTFETs, such as ION and IOFF, intrinsic delay, ION/IOFF ratio, power-delay product, unity-gain frequency, gate transconductance, and output resistance are investigated. The simulation results show that uniaxial stain, significantly alters the OFF state behavior and as a result the electrical properties of the device.
A modified structure for MOSFET-like carbon nanotube FET
Mirasanloo, Yousefi
4/15/2016
Conference
Journal
Applied physics A
Volume
Issue
Pages
Publisher
Springer
Description
In this paper, non-equilibrium Green’s function method is used to investigate the characteristics of carbon nanotube field-effect transistors (CNTFETs). Leakage current resulted from band-to-band tunneling, and ambipolarity behaviors are among the known effects for CNTFET devices. To minimize these phenomena, a modified structure is presented in which density of source and drain in the transistor is reduced in steps while going toward the intrinsic channel. The proposed structure shows a better ambipolar property and less power-delay product at a given I ON/I OFF ratio, and also less delay time at a given I ON compared with the available structure. Also, its other ON- and OFF-state characteristics are almost intact. Afterward, the effect of different factors on the behavior of the device and their optimal values such as channel length changes, chirality, dielectric constant, and gate length changes are investigated.
A novel Tunneling Graphene Nano Ribbon Field Effect Transistor with dual material gate: Numerical studies
Seyed Saleh Ghoreishi, Kamyar Saghafi, Reza Yousefi, Mohammad Kazem Moravvej-farshi
6/23/2016
Conference
Journal
Superlattices and Microstructures
Volume
97
Issue
Pages
277e286
Publisher
Academic Press
Description
Abstract In this work, we present Dual Material Gate Tunneling Graphene Nano-Ribbon Field Effect Transistors (DMG-T-GNRFET) mainly to suppress the am-bipolar current with assumption that sub-threshold swing which is one of the important characteristics of tunneling transistors must not be degraded. In the proposed structure, dual material gates with different work functions are used. Our investigations are based on numerical simulations which self-consistently solves the 2D Poisson based on an atomistic mode- ...
A computational study of a novel graphene nanoribbon field effect transistor
Reza Yousefi Seyed Saleh Ghoreishi
2/1/2017
Conference
Journal
International Journal of Modern Physics B
Volume
Issue
Pages
Publisher
World Scientific
Description
Performance Evaluation and Design Considerations of Electrically Activated Drain Extension Tunneling GNRFET: A Quantum Simulation Study
Neda Taghavi Seyed Saleh Ghoreishi, Reza Yousefi
7/24/2017
Conference
Journal
Journal of Electronic Materials
Volume
Issue
Pages
Publisher
Springer
Description
A numerical study of the nanoribbon field-effect transistors under the ballistic and dissipative transport
Habib Aderang Seyed Saleh Ghoreishi, Reza Yousefi, Kamyar Saghafi
8/20/2017
Conference
Journal
International Nano Letters
Volume
Issue
Pages
Publisher
springer
Description
An Analytical Model for Ballistic Carbon Nanotube Field Effect Transistor Applicable to Circuit Simulators
Reza Yousefi, Seyed Saleh Ghoreishi, Mostafa Kabir
12/1/2017
Conference
Journal
ECS Journal of Solid State Science and Technology
Volume
6
Issue
9
Pages
109-113
Publisher
ECS -- The Electrochemical Society
Description
FETToy is a numerical reference method used for modeling of the nano-transistors in the purely ballistic transport limit. Because of the existence of integral equation in the calculation of the charge distribution, there is no possibility of using this model in the commercially available circuit simulators, such as SPICE. A number of different analytical solutions for estimating the charge integral equation have been proposed. In this research, one of these models is modified in such a way that the proposed model has a higher accuracy in different conditions. Simulation results show that in terms of various physical parameters and bias values, the modified model exhibits superior accuracy in comparison with the abovementioned reference.
A Computational Study of an Optimized MOS-Like Graphene Nano Ribbon Field Effect Transistor (GNRFET)
Amin Khorshidsavar, Seyed Saleh Ghoreishi, Reza Yousefi
1/1/2018
Conference
Journal
ECS Journal of Solid State Science and Technology
Volume
7
Issue
3
Pages
96-101
Publisher
The Electrochemical Society
Description
The present paper introduces a metal-oxide-semiconductor graphene nanoribbon field-effect transistor (MOS-GNRFET), in which heterogeneous gates with different work functions have been used. In this structure, length of each gate was selected equal to 15 nm; moreover, work function of the gate close to the source and drain was selected equal to and 0.4 eV less than the graphene nanoribbon's work function, respectively. The simulation was performed using the non-equilibrium Green's function (NEGF) in the mode space approach. According to the simulation results, the proposed structure exhibited better ambipolar behavior and had less off-current compared with the conventional structure with the same dimensions. In addition, the hot electron effect is reduced in the proposed structure.
Gate structural engineering of MOS-like junctionless Carbon nanotube field effect transistor (MOS-like J-CNTFET)
Maryam Faraji, Seyed Saleh Ghoreishi, Reza Yousefi
1/2/2018
Conference
Journal
International Journal of Nano Dimension
Volume
9
Issue
1
Pages
32-40
Publisher
Islamic Azad University-Tonekabon Branch
Description
In this article, a new structure is presented for MOS (Metal Oxide Semiconductor)-like junctionless carbon nanotube field effect transistor (MOS-like J-CNTFET), in which dual material gate with different work-functions are used. In the aforementioned structure, the size of the gates near the source and the drain are 14 and 6 nm, respectively, and the work-functions are equal and 0.5 eV less than the work-function of the intrinsic carbon nanotube. The simulation is carried out in the ballistic regime using the non-equilibrium Green's function (NEGF) in the mode space approach. The simulation results show that the proposed structure has a better am-bipolar behavior and less OFF current compared to a conventional junctionless structure with the same dimensions. In the new structure, the hot carrier effect is also reduced due to the reduced electric field near the drain, and with regard to a peak in the electric field curve at the junction of two gates, the gate control on the channel will be increased.
A computational study of a carbon nanotube junctionless tunneling field-effect transistor (CNT-JLTFET) based on the charge plasma concept
Seyyedeh Hoda Tahaei, Seyed Saleh Ghoreishi, Reza Yousefi, Habib Aderang
1/1/2019
Conference
Journal
superlattices and microstructures
Volume
125
Issue
Pages
168-176
Publisher
Academic Press
Description
In this work, a carbon nanotube junctionless tunnel field-effect transistor has been proposed and investigated. The presented structure uses two isolated gates with the same work function (main gate (MG) and P-gate (PG)) which are separated by a 3 nm SiO 2 spacer. PG has a constant voltage and a constant length of 0.4 V and 12 nm, respectively which has been used for electrically activation of the source region to behave like a tunnel FET. Simulations show that in comparison with the conventional carbon nanotube tunnel field-effect transistor (CNT-TFET) and carbon nanotube tunnel field-effect transistor with hetero-gate dielectric (HGD-CNT-TFET) suggested structure has significant higher ON current and improvement in ambipolar behavior. Furthermore, analog characteristics like unity gain frequency (f t) and transconductance (g m) have been improved considerably.