Field emitters with low turn on electric field based on carbon fibers

2007 ◽  
Vol 253 (14) ◽  
pp. 5980-5984 ◽  
Author(s):  
Qilong Wang ◽  
Hui Mu ◽  
Xiaobing Zhang ◽  
Wei Lei ◽  
Jinchan Wang ◽  
...  
Keyword(s):  
Electric Field ◽  
Carbon Fibers ◽  
Turn On ◽  
Field Emitters

BRIDGING OF CARBON FIBERS IN CF/EPOXY COMPOSITES USING ELECTROSTATICALLY INDUCED CNT ALIGNMENT

2021 ◽  
Author(s):  
DANDAN ZHANG ◽  
XINGKANG SHE ◽  
YIPENG HE ◽  
WESLEY A. CHAPKIN, ◽  
VI T. BREGMAN ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Electric Field ◽  
Carbon Fibers ◽  
Hybrid Composites ◽  
Tensile Modulus ◽  
Tensile Tests ◽  
Polymer Mixture ◽  
Ac Electric Field ◽  
Reinforced Polymer ◽  
Electric Field Direction

Carbon fiber reinforced polymer (CFRP) composites are lightweight materials with superior strength but are expensive due to the increased cost of carbon fibers (CFs). The addition of carbon nanotubes (CNTs) to polymer nanocomposites are becoming an excellent alternative to CF due to their unique combination of electrical, thermal, and mechanical properties. With the application of an electric field across the CNT/polymer mixture before curing, CNTs will not only be aligned along the electric field direction, but also form networks after reaching to a certain degree of alignment. In this study, an alternating current (AC) electric field was applied continuously to CNT/CF/Epoxy hybrid composites before curing. By cutting off the applied voltage when the monitored electric current increased, the degree of networking of CNTs between two CF tows was controlled. The relative electric field strength around the end of conductive carbon fiber tows in the epoxy matrix was modeled using COMSOL Multiphysics. It increased after applying AC electric field parallel to the CF tows, thereby increasing the alignment degree of CNTs and building a network to bridge the CF tows. The preliminary results indicate that the microhardness and tensile modulus between two CF tows are increased due to the networking of CNTs in this area. The fracture surface of the specimens after tensile tests were characterized to reveal more details of the microstructure.

Field-Emission Triode of Tetrapod-Like ZnO Film Using Metal Mesh

2011 ◽  
Vol 233-235 ◽  
pp. 2600-2603 ◽  
Author(s):  
Li An Ma ◽  
Chao Xing Wu ◽  
Jin Yang Lin ◽  
Li Qin Hu ◽  
Tai Liang Guo
Keyword(s):  
Chemical Vapor Deposition ◽  
Field Emission ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Raw Material ◽  
Anode Current ◽  
Zno Film ◽  
Metal Mesh ◽  
Turn On ◽  
Field Emitters

Using Zn powder as the raw material, Tetrapod-like ZnO nanoneedles with controllable morphology and size were successfully prepared by chemical vapor deposition. A screen printed normal-gated triode with Tetrapod-like ZnO nanoneedles field emitters is demonstrated. Field emission measurements show that the Tetrapod-like ZnO nanoneedles FED triode devices posses a good field emission property. The turn-on voltage is 270V. An anode current of 2.75 mA and a gate current of 0.43 mA are extracted at a gate voltage of 600 V with a brightness of 2300 cd/m2.

scholarly journals A Novel MOS-Channel Diode Embedded in a SiC Superjunction MOSFET for Enhanced Switching Performance and Superior Short Circuit Ruggedness

Electronics ◽  
2021 ◽  
Vol 10 (21) ◽  
pp. 2619
Author(s):  
Jongwoon Yoon ◽  
Kwangsoo Kim
Keyword(s):  
Electric Field ◽  
Switching Time ◽  
Short Circuit ◽  
Oxide Thickness ◽  
Shielding Effect ◽  
Figures Of Merit ◽  
Switching Performance ◽  
Turn On ◽  
Reverse Recovery Time ◽  
Tcad Simulations

In this study, a novel MOS-channel diode embedded in a SiC superjunction MOSFET (MCD SJ-MOSFET) is proposed and analyzed by means of numerical TCAD simulations. Owing to the electric field shielding effect of the P+ body and the P-pillar, the channel diode oxide thickness (tco) of MCD can be set to very thin while achieving a low maximum oxide electric field (EMOX) under 3 MV/cm. Therefore, the turn-on voltage (VF) of the proposed structure was 1.43 V, deactivating the parasitic PIN body diode. Compared with the SJ-MOSFET, the reverse recovery time (trr) and the reverse recovery charge (Qrr) were improved by 43% and 59%, respectively. Although there is a slight increase in specific on-resistance (RON), the MCD SJ-MOSFET shows very low input capacitance (CISS) and gate to drain capacitance (CGD) due to the reduced active gate. Therefore, significantly improved figures of merit RON × CGD by a factor of 4.3 are achieved compared to SJ-MOSFET. As a result, the proposed structure reduced the switching time as well as the switching energy loss (ESW). Moreover, electro-thermal simulation results show that the MCD SJ-MOSFET has a short circuit withstand time (tSC) more than twice that of the SJ-MOSFET at various DC bus voltages (400 and 600 V).

Vertically aligned self-assembled gold nanorods as low turn-on, stable field emitters

2015 ◽  
Vol 355 ◽  
pp. 978-983 ◽  
Author(s):  
Amey Apte ◽  
Padmashree Joshi ◽  
Prashant Bhaskar ◽  
Dilip Joag ◽  
Sulabha Kulkarni
Keyword(s):  
Gold Nanorods ◽  
Turn On ◽  
Field Emitters ◽  
Vertically Aligned ◽  
Self Assembled ◽  
Stable Field

SiC-MOSFET Structure Enabling Fast Turn-On and -Off Switching

2012 ◽  
Vol 717-720 ◽  
pp. 1097-1100 ◽  
Author(s):  
Shiro Hino ◽  
Naruhisa Miura ◽  
Akihiko Furukawa ◽  
Shoyu Watanabe ◽  
Yukiyasu Nakao ◽  
...  
Keyword(s):  
Electric Field ◽  
Equivalent Circuit ◽  
High Speed ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Turn On ◽  
Model Based ◽  
Switching Losses ◽  
High Speed Switching

High speed switching is desired to reduce switching losses of SiC-MOSFETs. In order to realize SiC-MOSFETs capable of high speed switching, we numerically evaluated the electric field induced in SiC-MOSFETs during switching using an equivalent circuit model. Based on the evaluation, we designed a SiC-MOSFET, which successfully demonstrated high speed switching with a dV/dt of over 70 V/ns.

Synthesis of Carbon–Nitrogen Nanostructures by Hot Isostatic Pressure Apparatus and Their Field Emission Properties

2007 ◽  
Vol 7 (2) ◽  
pp. 570-574
Author(s):  
Yang Doo Lee ◽  
V. D. Blank ◽  
D. V. Batov ◽  
S. G. Buga ◽  
Yun-Hi Lee ◽  
...  
Keyword(s):  
Field Emission ◽  
Field Enhancement ◽  
Glass Frit ◽  
Gas Mixture ◽  
Nitrogen Gas ◽  
Field Emission Properties ◽  
Turn On ◽  
Field Emitters ◽  
Enhancement Factors ◽  
Resistive Heater

Carbon–nitrogen (CN) nanofibers were synthesized in argon–nitrogen gas mixture at 75 MPa by high isostatic pressure (HIP) apparatus using a graphite resistive heater. The CN nanofibers were grown in random with the diameter of about 200 nm and the length over 5 μm. The structures obtained can be divided bamboo-like, spring-like, and bead necklace-like CN nanofibers. The nitrogen content of up to 8.4% was found in CN nanofibers by EELS analysis. Field emission results showed that the density of field emitters and the field enhancement factors changed by surface treatments and that CN nanofibers contained glass frit. The screen-printed CN nanofiber had a turn-on field of 2 V/μm.

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