Microscopic Study on the Mechanism of Ultrasonic Nanowelding

2010 ◽  
Vol 97-101 ◽  
pp. 3928-3931 ◽  
Author(s):  
Xuan Liu ◽  
Li Jie Zhao ◽  
Hua Zhou
Keyword(s):  
Molecular Dynamics ◽  
High Frequency ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Single Wall Carbon Nanotubes ◽  
Metal Electrodes ◽  
Softening Effect ◽  
Acoustic Softening ◽  
Dynamics Method ◽  
Ultrasonic Parameter

Using molecular dynamics method, the progress of bonding single-wall carbon nanotubes and metal electrodes by ultrasonic nanowelding technique is described completely at atomistic length scales. The temperature distribution in electrodes is analyzed. The maximal temperature of electrode atoms is about 570.1K. The mechanism responsible for ultrasonic nanowelding is revealed as the result of the high-frequency ultrasonic energy softening the metal and causing plastic deformation of the metal under the clamping stress because of the ‘acoustic softening effect’. The ultrasonic parameter is optimized, which is important in improving the performance of carbon nanotube field-effect transistors and building reliable nanodevices.

High-frequency equivalent circuits of junction-gate field-effect transistors

1970 ◽  
Vol 6 (18) ◽  
pp. 590
Author(s):  
P.U. Calzolari ◽  
S. Graffi ◽  
A. Mazzone
Keyword(s):  
High Frequency ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Equivalent Circuits

scholarly journals Experimental and molecular dynamics studies of an ultra-fast sequential hydrogen plasma process for fabricating phosphorene-based sensors

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Rajabali ◽  
H. Asgharyan ◽  
V. Fadaei Naeini ◽  
A. Boudaghi ◽  
B. Zabihi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Dynamics ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Hydrogen Plasma ◽  
Device Fabrication ◽  
Dynamics Simulation ◽  
Red Phosphorus ◽  
Large Area ◽  
Low Concentration

AbstractLow concentration phosphorene-based sensors have been fabricated using a facile and ultra-fast process which is based on an exfoliation-free sequential hydrogen plasma treatment to convert the amorphous phosphorus thin film into mono- or few-layered phosphorene sheets. These sheets have been realized directly on silicon substrates followed by the fabrication of field-effect transistors showing the low leakage current and reasonable mobility for the nano-sensors. Being capable of covering the whole surface of the silicon substrate, red phosphorus (RP) coated substrate has been employed to achieve large area phosphorene sheets. Unlike the available techniques including mechanical exfoliation, there is no need for any exfoliation and/or transfer step which is significant progress in shortening the device fabrication procedure. These phosphorene sheets have been examined using transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Raman spectroscopy and atomic-force microscopy (AFM). Electrical output in different states of the crystallization as well as its correlation with the test parameters have been also extensively used to examine the evolution of the phosphorene sheets. By utilizing the fabricated devices, the sensitivity of the phosphorene based-field effect transistors to the soluble L-Cysteine in low concentrations has been studied by measuring the FET response to the different concentrations. At a gate voltage of − 2.5 V, the range of 0.07 to 0.60 mg/ml of the L-Cysteine has been distinguishably detected presenting a gate-controlled sensor for a low-concentration solution. A reactive molecular dynamics simulation has been also performed to track the details of this plasma-based crystallization. The obtained results showed that the imparted energy from hydrogen plasma resulted in a phase transition from a system containing red phosphorus atoms to the crystal one. Interestingly and according to the simulation results, there is a directional preference of crystal growth as the crystalline domains are being formed and RP atoms are more likely to re-locate in armchair than in zigzag direction.

scholarly journals Numerical Evaluation of the Effect of Geometric Tolerances on the High-Frequency Performance of Graphene Field-Effect Transistors

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3121
Author(s):  
Monica La Mura ◽  
Patrizia Lamberti ◽  
Vincenzo Tucci
Keyword(s):  
High Frequency ◽  
Communication Systems ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Field Effect Transistors ◽  
Channel Length ◽  
Geometrical Parameters ◽  
Effect Transistor ◽  
Rf Performance ◽  
The Impact

The interest in graphene-based electronics is due to graphene’s great carrier mobility, atomic thickness, resistance to radiation, and tolerance to extreme temperatures. These characteristics enable the development of extremely miniaturized high-performing electronic devices for next-generation radiofrequency (RF) communication systems. The main building block of graphene-based electronics is the graphene-field effect transistor (GFET). An important issue hindering the diffusion of GFET-based circuits on a commercial level is the repeatability of the fabrication process, which affects the uncertainty of both the device geometry and the graphene quality. Concerning the GFET geometrical parameters, it is well known that the channel length is the main factor that determines the high-frequency limitations of a field-effect transistor, and is therefore the parameter that should be better controlled during the fabrication. Nevertheless, other parameters are affected by a fabrication-related tolerance; to understand to which extent an increase of the accuracy of the GFET layout patterning process steps can improve the performance uniformity, their impact on the GFET performance variability should be considered and compared to that of the channel length. In this work, we assess the impact of the fabrication-related tolerances of GFET-base amplifier geometrical parameters on the RF performance, in terms of the amplifier transit frequency and maximum oscillation frequency, by using a design-of-experiments approach.

scholarly journals Does carrier velocity saturation help to enhance fmax in graphene field-effect transistors?

2020 ◽  
Vol 2 (9) ◽  
pp. 4179-4186 ◽  
Author(s):  
Pedro C. Feijoo ◽  
Francisco Pasadas ◽  
Marlene Bonmann ◽  
Muhammad Asad ◽  
Xinxin Yang ◽  
...  
Keyword(s):  
High Frequency ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Drift Diffusion Model ◽  
Drift Diffusion ◽  
Velocity Saturation ◽  
Self Heating ◽  
Heating Effects ◽  
Carrier Velocity ◽  
High Frequency Performance

A drift–diffusion model including self-heating effects in graphene transistors to investigate carrier velocity saturation for optimal high frequency performance.

scholarly journals Small-Signal Capacitance and Current Parameter Modeling in Large-Scale High-Frequency Graphene Field-Effect Transistors

2013 ◽  
Vol 60 (6) ◽  
pp. 1799-1806 ◽  
Author(s):  
Gennady I. Zebrev ◽  
Alexander A. Tselykovskiy ◽  
Daria K. Batmanova ◽  
Evgeny V. Melnik
Keyword(s):  
High Frequency ◽  
Field Effect ◽  
Large Scale ◽  
Field Effect Transistors ◽  
Small Signal ◽  
Current Parameter

Light-Emitting Field-Effect Transistors Having Metal Electrodes Modified with an Organic Thin Film

2012 ◽  
Vol 51 (4S) ◽  
pp. 04DK07 ◽  
Author(s):  
Akinori Okada ◽  
Yoshihide Fukaya ◽  
Shu Hotta ◽  
Takeshi Yamao
Keyword(s):  
Thin Film ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Organic Thin Film ◽  
Metal Electrodes ◽  
Light Emitting
Sign in / Sign up

Export Citation Format

Share Document