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Field Emission Characteristics of the Structure of Vertically Aligned Carbon Nanotube Bundles.

Lin PH, Sie CL, Chen CA, Chang HC, Shih YT, Chang HY, Su WJ, Lee KY - Nanoscale Res Lett (2015)

Bottom Line: In this study, we performed thermal chemical vapor deposition for growing vertically aligned carbon nanotube (VACNT) bundles for a field emitter and applied photolithography for defining the arrangement pattern to simultaneously compare square and hexagonal arrangements by using two ratios of the interbundle distance to the bundle height (R) of field emitters.The fluorescent images of the synthesized VACNT bundles manifested the uniformity of FE currents.The results of our study indicate the feasibility of applying the VACNT field emitter arrangement to achieve optimal FE performance.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, No. 43, Sec. 4, Keelung Road, Taipei, 10607, Taiwan, plin21@mail.ntust.edu.tw.

ABSTRACT
In this study, we performed thermal chemical vapor deposition for growing vertically aligned carbon nanotube (VACNT) bundles for a field emitter and applied photolithography for defining the arrangement pattern to simultaneously compare square and hexagonal arrangements by using two ratios of the interbundle distance to the bundle height (R) of field emitters. The hexagon arrangement with R = 2 had the lowest turn-on electric field (E to) and highest enhancement factor, whereas the square arrangement with R = 3 had the most stable field emission (FE) characteristic. The number density can reveal the correlation to the lowest E to and highest enhancement factor more effectively than can the R or L. The fluorescent images of the synthesized VACNT bundles manifested the uniformity of FE currents. The results of our study indicate the feasibility of applying the VACNT field emitter arrangement to achieve optimal FE performance.

No MeSH data available.


SEM images of VACNT bundles. a An isolated cylindrical CNT bundle. b The bottom of the CNT bundle. c CNT bundles arranged in an interval three times their height. d CNT bundles arranged in an interval two times their height
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Fig2: SEM images of VACNT bundles. a An isolated cylindrical CNT bundle. b The bottom of the CNT bundle. c CNT bundles arranged in an interval three times their height. d CNT bundles arranged in an interval two times their height

Mentions: Figure 2a shows the SEM image of a single VACNT bundle. The shape of the VACNT bundle was cylindrical, and the diameter and height were 10 and 15 μm, respectively. Figure 2b shows an enlarged SEM image of Fig. 2a. The bundle was vertically aligned with the Si substrate; it consisted of VACNTs with a high number density of approximately 109 cm−2, which was examined using the magnified SEM image of the bottom region. The applied electric field varied acutely in the peripheral edge of the VACNT bundle because of a screening effect. Consequently, the VACNT bundle could be almost treated as an isolated emitter [12]. Moreover, because the height of the VACNT bundles was fixed as 15 μm, according to the designed pattern, the ratios of L to H were three and two, as shown in Fig. 2c, d, respectively.Fig. 2


Field Emission Characteristics of the Structure of Vertically Aligned Carbon Nanotube Bundles.

Lin PH, Sie CL, Chen CA, Chang HC, Shih YT, Chang HY, Su WJ, Lee KY - Nanoscale Res Lett (2015)

SEM images of VACNT bundles. a An isolated cylindrical CNT bundle. b The bottom of the CNT bundle. c CNT bundles arranged in an interval three times their height. d CNT bundles arranged in an interval two times their height
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4504873&req=5

Fig2: SEM images of VACNT bundles. a An isolated cylindrical CNT bundle. b The bottom of the CNT bundle. c CNT bundles arranged in an interval three times their height. d CNT bundles arranged in an interval two times their height
Mentions: Figure 2a shows the SEM image of a single VACNT bundle. The shape of the VACNT bundle was cylindrical, and the diameter and height were 10 and 15 μm, respectively. Figure 2b shows an enlarged SEM image of Fig. 2a. The bundle was vertically aligned with the Si substrate; it consisted of VACNTs with a high number density of approximately 109 cm−2, which was examined using the magnified SEM image of the bottom region. The applied electric field varied acutely in the peripheral edge of the VACNT bundle because of a screening effect. Consequently, the VACNT bundle could be almost treated as an isolated emitter [12]. Moreover, because the height of the VACNT bundles was fixed as 15 μm, according to the designed pattern, the ratios of L to H were three and two, as shown in Fig. 2c, d, respectively.Fig. 2

Bottom Line: In this study, we performed thermal chemical vapor deposition for growing vertically aligned carbon nanotube (VACNT) bundles for a field emitter and applied photolithography for defining the arrangement pattern to simultaneously compare square and hexagonal arrangements by using two ratios of the interbundle distance to the bundle height (R) of field emitters.The fluorescent images of the synthesized VACNT bundles manifested the uniformity of FE currents.The results of our study indicate the feasibility of applying the VACNT field emitter arrangement to achieve optimal FE performance.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, No. 43, Sec. 4, Keelung Road, Taipei, 10607, Taiwan, plin21@mail.ntust.edu.tw.

ABSTRACT
In this study, we performed thermal chemical vapor deposition for growing vertically aligned carbon nanotube (VACNT) bundles for a field emitter and applied photolithography for defining the arrangement pattern to simultaneously compare square and hexagonal arrangements by using two ratios of the interbundle distance to the bundle height (R) of field emitters. The hexagon arrangement with R = 2 had the lowest turn-on electric field (E to) and highest enhancement factor, whereas the square arrangement with R = 3 had the most stable field emission (FE) characteristic. The number density can reveal the correlation to the lowest E to and highest enhancement factor more effectively than can the R or L. The fluorescent images of the synthesized VACNT bundles manifested the uniformity of FE currents. The results of our study indicate the feasibility of applying the VACNT field emitter arrangement to achieve optimal FE performance.

No MeSH data available.