Browsing by Author "Juan, CP"

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Effects of high-density oxygen plasma posttreatment on field emission properties of carbon nanotube field-emission displays
(2005-11-01)
Juan, CP
;
Tsai, CC
;
Chen, KH
;
Chen, LC
;
Cheng, HGC
The effects of oxygen plasma posttreatment (PPT) on the morphology and field emission properties of carbon nanotube (CNT) arrays grown on silicon substrates are proposed and experimental results are reported. Oxygen PPT led to an enhancement in the emission properties of CNTs, which showed an increase in total emission current density and a decrease in turn-on field after plasma treatment. Scanning electron microscopy (SEM) images showed reduced densities of the CNTs, which resulted in a decrease of the screening effect in the electric field. Raman spectra showed an increase in the number of defects which served as field-emission sites when the plasma power or treatment time with the plasma increased. Transmission electron microscopy (TEM) images were used to identify the quality of the nanotubes, so that we could clearly find evidences of improvement in the field emission properties after plasma treatment. The measurement of electrical characteristics revealed improved field emission properties under proper plasma conditions. The turn-on field decreased from 4.8 to 2.5 V/mu m, and the emission current density increased from 78.7 mu A/cm(2) to 18 mA/cm(2) at an applied field of 5.5 V/mu m.
Fabrication and characterization of lateral field emission device based on carbon nanotubes
(2003)
Tsai, CC
;
Juan, CP
;
Chen, KJ
;
Chen, KH
;
Chen, LC
Fabrication and characterization of lateral field emission device based on carbon nanotubes
(2005-04-01)
Juan, CP
;
Tsai, CC
;
Chen, KH
;
Chen, LC
;
Cheng, HC
We have proposed and fabricated a vertical lateral field emission device (LFED) based on carbon nanotubes (CNTs). It combines high-performance nanomaterials with mature solid-state fabrication technology to produce miniaturized vacuum devices with superior field emission characteristics. The techniques employed are very simple and allow for good reproducibility in controlling the short distance from the polysilicon anode to the CNTs cathode inter-electrode distance. The inter-electrode gap can be easily fabricated to be less than 1 mu m by a wet etching process without using fine lithography. The CNTs were selectively grown using a microwave-plasma enhanced chemical vapor deposition system (MPCVD). The anode-to-emitter gap distance and the length of carbon nanotubes are well controlled to enable investigation of their effect on the field emission properties. The turn-on voltage of the fabricated device with an inter-electrode gap of 0.53 mu m is as low as 0.2V, and the emission current is as high as 9.72mA at 10V. The emission current fluctuation is approximately +/- 3.5% for 1500s.
Growth and characterization of tungsten carbide nanowires by thermal annealing of sputter-deposited WCx films
(2004-09-20)
Wang, SJ
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Chen, CH
;
Chang, SC
;
Uang, KM
;
Juan, CP
In this letter, the growth of dense W2C nanowires by a simple thermal annealing of sputter-deposited WCx films in nitrogen ambient is reported. Straight nanowires with a density of 250-260 mum(-2) and length/diameter in the range of 0.2-0.3 mum/13-15 nm were obtained from the 700degreesC-annealed samples, which exhibit good electron field emission characteristics with a typical turn-on field of about 1.7 V/mum. The self-catalytic growth of W2C nanowires is attributed to the formation of alpha-W2C phase caused by carbon depletion in the WCx films during thermal annealing. (C) 2004 American Institute of Physics.
Improved field-emission properties of carbon nanotube field-emission arrays by controlled density growth,of carbon nanotubes
(2005-01-01)
Juan, CP
;
Chen, KJ
;
Tsai, CC
;
Lin, KC
;
Hong, WK
The density distribution of CNTs is one of the. crucial parameters determing the field-emission property of CNTs. To effectively control the density of CNTs, an inactive thin-film layer was deposited on a catalyst. The results showed that improved field emission property could be obtained with a thin SiO layer on the catalyst layer as the precursor. For 3.5 nm Fe and 3.5 nm SiO on 3.5 nm Fe as a catalyst, the turn-on field could be decreased from 3.7 V/mum. to 2.2 V/mum and the field-emission current density increased from 2.6 x 10(-8) A/cm(2) to 2.4 x 10(-4) A/cm(2) when the applied field was 4 V/mum.