Browsing by Author "Chang, Pei-Chi"

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Improvement of luminescent uniformity via synthesizing the carbon nanotubes on a Fe-TiCo-deposited catalytic layer
(2007-02-01)
Cheng, Huang-Chung
;
Lai, Rui-Ling
;
Chang, Yao-Ren
;
Lin, Kao-Chao
;
Juan, Chuan-Ping
Uniformity has been considered to be one of the most important criteria for carbon nanotubes (CNTs) to be utilized as the emitters in field-emission displays (FEDs) or backlight units (BLUs). Using co-deposited Fe and Ti film as a catalyst, a uniform distribution of catalytic nanoparticles was obtained after hydrogen pretreatment as compared with nanoparticles obtained only using a pure Fe film. It might be attributed to the suppression of coalescence of the Fe nanoparticles in the codeposited Fe-Ti film during the CNTs growth. In addition, the length variation of the CNTs synthesized by thermal-chemical vapor deposition (thermal-CVD) was also remarkably Suppressed. This resulted in a significant improvement of the luminescent uniformity, and homogeneous light emission was obtained front the CNTs at 700 V.
Pillar-shaped carbon nanotubes by Ti-Fe codeposition
(2007)
Chang, Pei-Chi
;
Lai, Rui-Ling
;
Lee, Chien-Ying
;
Lin, Kao-Chao
;
Chen, Hsia-Wei
In this report, the pillar-shaped carbon nanotubes (CNTs) have been achieved by utilizing an Fe-Ti codeposited layer as catalyst in thermal chemical vapor deposition system (T-CVD). By adjusting the ratio of distance between neighboring pillars (R) to the pillar height (H) as 2.5, the field emission characteristics can be effectively improved by reducing the screening effect. The turn-on field was remarkably decreased to 0.95 V/um with a very high current of 4.98mA for a device with area of 0.02cm(2). The coefficient of variation (CV) of the emission current was as low as 20.59% at 800V for 3600sec.
Properties of carbon nanotubes via a thin Ti capping layer on the pretreated catalyst
(2007)
Lai, Rui-Ling
;
Shiu, Jiun-Kai
;
Chang, Yao-Ren
;
Lin, Kao-Chao
;
Chang, Pei-Chi
Screening effect and reliability are two of the most important issues in carbon nanotube-based field-emission devices. A thin Ti capping layer has been deposited on the hydrogen-pretreated catalytic iron nanoparticles to control the density of subsequently grown carbon nanotubes. In this way, the screening effect can be remarkably reduced due to the density of carbon nanotubes down to 10(7) from 10(9) cm(-2) as compared to the control specimens. Thus, the turn-on field can be improved to be 2.1 from 3.8 V/mu m at the emission current density of 10 mu A/cm(2). Furthermore, the electrical breakdown field can be increased to more than 7 V/mu m and the lifetime of carbon nanotubes at high electric field (10 V/mu m) can be greatly prolonged from a few seconds to more than 1 h. This can be attributed to better adhesion and lower contact resistance between the carbon nanotubes and the substrate. (c) 2007 The Electrochemical Society. All rights reserved.
The reliability improvements of carbon nanotubes emitters by utilizing an Fe-Ti codeposited catalyst
(2007-08-01)
Lai, Rui-Ling
;
Shiu, Jiun-Kai
;
Chang, Yao-Ren
;
Lin, Kao-Chao
;
Chang, Pei-Chi
In this report, carbon nanotubes (CNTs) partially immersed into the codeposited metal layer have been synthesized by utilizin- an Fe-Ti codeposited catalyst in a thermal -chemical vapor deposition system. This structure could enlarge the contact area between CNTs and substrates to provide better adhesion properties than that in the case of CNTs synthesized from a pure Fe film. Therefore, an abrupt decrease in emission current due to mechanical destruction at a high electric field and a gradual degradation in emission current due to Joule heating were remarkably suppressed. A stable emission current of about 30mA/cm(2) at 7.7 V/mu m for 2,500 s was obtained without obvious degradation.