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UPSI Digital Repository (UDRep)
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| Abstract : Universiti Pendidikan Sultan Idris |
| 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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