| Budget Amount *help |
¥45,500,000 (Direct Cost: ¥35,000,000、Indirect Cost: ¥10,500,000)
Fiscal Year 2007: ¥7,020,000 (Direct Cost: ¥5,400,000、Indirect Cost: ¥1,620,000)
Fiscal Year 2006: ¥11,050,000 (Direct Cost: ¥8,500,000、Indirect Cost: ¥2,550,000)
Fiscal Year 2005: ¥27,430,000 (Direct Cost: ¥21,100,000、Indirect Cost: ¥6,330,000)
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| Research Abstract |
Analysis in the initial phase, and morphology and construction control of carbon nanowalls (CNWs), which are new two-dimensional carbon nanostructures, were investigated for applying the carbon nanowalls to the field emission devices. In addition, hydrogen plasma process, magnesium dioxide coating, and nitrogen doping were carried out to realizing the CNWs with higher field emission properties.
By the analysis of initial growth process using a spectroscopic ellipsometer, it was found that the diamond-like carbon (DIE) thin film formed in the early phase, and then carbon nanowalls constructed by graphene sheets grew up. It was confirmed that the average distance between each CNW and the crystallized structure of graphene sheets were dependence on the pressure, the input power, deposition time of CNWs etc. On the basis of these results, we succeeded in control of morphology and structure of CNWs. From the results of investigation about the effect of the morphology of CNWs on the field emission property, the best performance was realized in the case that the ratio of the height of wall to the distance between walls was 1. Moreover the fabrication of CNWs without the thin film grown in the initial phase using a electron beam excited plasma (EBEP), in addition those CNWs were extremely thin, e. g., a few nm, and completely vertical from the bottom to the surface.
The field emission properties of the previous CNWs were a threshold voltage of 6.0 V/μm and current density of 2 μA/cm^2. In this study, those properties were improved to 3.7 V/μm and 10 μA/cm^2, respectively, by hydrogen plasma process after CNWs deposition and magnesium dioxide coating on CNWs. Furthermore, the CNWs with nitrogen doping has the higher current density of 〜1 mA/cm^2. These CNWs have a property enough for applying to the field emission devices.
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