ENHANCEMENT OF FIELD ELECTRON EMISSION PROPERTIES OF CARBON NANOTUBES/ZINC OXIDE NANOCOMPOSITES USING SINGLE AND MULTI-STEP METHODS
This study aimed to enhance the field electron emission (FEE) properties of carbon nanotubes (CNTs) synthesized from waste cooking palm oil combined with zinc oxide (ZnO) to produce CNTs/ZnO nanocomposites. The methods used in this study were single and multi-step depositions. The single-step dep...
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| Format: | Thesis |
| Published: |
2015
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| Subjects: | |
| Online Access: | http://pustaka2.upsi.edu.my/eprints/796/ http://pustaka2.upsi.edu.my/eprints/796/1/ENHANCEMENT%20OF%20FIELD%20ELECTRON%20EMISSION%20PROPERTIES%20OF%20CARBON%20NANOTUBES%20ZINC%20OXIDE%20NANOCOMPOSITES%20USING%20SINGLE%20AND%20MULTI%20STEP%20METHODS.pdf |
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| Summary: | This study aimed to enhance the field electron emission (FEE) properties of carbon
nanotubes (CNTs) synthesized from waste cooking palm oil combined with zinc oxide
(ZnO) to produce CNTs/ZnO nanocomposites. The methods used in this study were
single and multi-step depositions. The single-step deposition method was done by
directly mixing the CNTs and ZnO precursors and they were synthesized using
thermal chemical vapor deposition (TCVD) method for 30 minutes. Meanwhile, the
multi-step deposition process was carried out by combining TCVD and sol-gel
immersion methods to fabricate CNTs/ZnO nanocomposites. There were three
different ZnO nanostructures namely nanorods, nanoflowers and nanorods-nanoflakes
which were composited with CNTs via multi-step deposition process. The obtained
samples were analyzed using electron microscopy, energy dispersive X-ray, micro-
Raman spectroscopy, X-ray diffraction spectroscopy, photoluminescence
spectroscopy and four-point probe current-voltage measurement. The field emission
properties of the samples were also studied using FEE measurement. The findings
showed that the turn-on and threshold fields of CNTs/ZnO nanocomposites decreased
as compared to pristine CNTs. Other than that, different nanostructures of ZnO
contributed to the FEE performance of CNTs/ZnO nanocomposites. The best FEE
properties were given by the growth of CNTs on ZnO nanoflowers, which has the
lowest turn-on field of 0.8 V/m at current density of 1 A/cm2 and a high field
enhancement factor of 9417. Larger emission site density and lower screening effect
in this sample were believed to affect the FEE performance. As a conclusion, the
fabrication of CNTs/ZnO nanocomposites have successfully enhanced the FEE
properties of CNTs. Implication of this study is that it provide a new insight on
advancing the synthesis of CNTs/ZnO nanocomposites for electron emission devices. |
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