A Low-Voltage, Premodulation Terahertz Oscillator Based on a Carbon Nanotube Cold Cathode

2020 ◽  
Vol 67 (3) ◽  
pp. 1266-1269 ◽  
Author(s):  
Xiaotao Xu ◽  
Xuesong Yuan ◽  
Qingyun Chen ◽  
Matthew T. Cole ◽  
Yu Zhang ◽  
...  
Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1768 ◽  
Author(s):  
Yifan Zu ◽  
Xuesong Yuan ◽  
Xiaotao Xu ◽  
Matthew T. Cole ◽  
Yu Zhang ◽  
...  

Carbon nanotube (CNT) cold cathodes are proving to be compelling candidates for miniaturized terahertz (THz) vacuum electronic devices (VEDs) owning to their superior field-emission (FE) characteristics. Here, we report on the development of a multi-sheet beam CNT cold cathode electron optical system with concurrently high beam current and high current density. The microscopic FE characteristics of the CNT film emitter is captured through the development of an empirically derived macroscopic simulation model which is used to provide representative emission performance. Through parametrically optimized macroscale simulations, a five-sheet-beam triode electron gun has been designed, and has been shown to emit up to 95 mA at 3.2 kV. Through careful engineering of the electron gun geometric parameters, a low-voltage compact THz radiation source operating in high-order TM 5 , 1 mode is investigated to improve output power and suppress mode competition. Particle in cell (PIC) simulations show the average output power is 33 W at 0.1 THz, and the beam–wave interaction efficiency is approximately 10%.


Author(s):  
T. Miyokawa ◽  
S. Norioka ◽  
S. Goto

Field emission SEMs (FE-SEMs) are becoming popular due to their high resolution needs. In the field of semiconductor product, it is demanded to use the low accelerating voltage FE-SEM to avoid the electron irradiation damage and the electron charging up on samples. However the accelerating voltage of usual SEM with FE-gun is limited until 1 kV, which is not enough small for the present demands, because the virtual source goes far from the tip in lower accelerating voltages. This virtual source position depends on the shape of the electrostatic lens. So, we investigated several types of electrostatic lenses to be applicable to the lower accelerating voltage. In the result, it is found a field emission gun with a conical anode is effectively applied for a wide range of low accelerating voltages.A field emission gun usually consists of a field emission tip (cold cathode) and the Butler type electrostatic lens.


Nano Futures ◽  
2021 ◽  
Author(s):  
Luis Portilla ◽  
Jianwen Zhao ◽  
Jing Zhao ◽  
Luigi Occhipinti ◽  
Vincenzo Pecunia

Nanomaterials ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 13 ◽  
Author(s):  
Xuesong Yuan ◽  
Matthew Cole ◽  
Yu Zhang ◽  
Jianqiang Wu ◽  
William Milne ◽  
...  
Keyword(s):  

Author(s):  
Feng Gao ◽  
Jianmin Qu ◽  
Matthew Yao

The carbon nanotube (CNT) is becoming a promising candidate as electrical interconnects in nanoscale electronics. This paper reports the electronic structure and the electrical conducting properties at the interface between an open-end single wall CNT (SWCNT) and various metal electrodes, such as Al, Au, Cu, and Pd. A simulation cell consisting of an SWCNT with each end connected to the metal electrode was constructed. A voltage bias is prescribed between the left- and right-electrodes to compute the electronic conductance. Due to the electronic structure, the electron density and local density of states (LDOS) are calculated to reveal the interaction behavior at the interfaces. The first-principle quantum mechanical density functional and non-equilibrium Green’s function (NEGF) approaches are adopted to compute the transport coefficient. After that, the voltage-current relation is calculated using the Landauer-Buttiker formalism. The results show that electrons are conducted through the electrode/CNT/electrode two-probe system. The contact electronic resistance is calculated by averaging the values in the low voltage bias regime (0.0–0.1 V), in which the voltage–current relationship is found to be linear. And the electrical contact conductance of electrode/CNT/electrode system show the electrode-type dependent, however, the amplitude for different electrodes is of the same order.


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