the effects of oxidizers on the diameters of the carbon nanotubes ...

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Figure 2.8. Possible vector space specified by <strong>the</strong> pairs <strong>of</strong> integers (n, m) for general CNTs (Source: Dresselhaus, et al. 1998) 2.3. Carbon Nanotube Syn<strong>the</strong>sis Methods Since <strong>the</strong> discovery <strong>of</strong> CNTs, several different production methods, <strong>the</strong> most common <strong>of</strong> which are arc-discharge (Journet and Bernier 1998), <strong>the</strong> laser-ablation (Thess, et al. 1996) and chemical vapor deposition (CVD) (Niu and Fang 2006), have been used to syn<strong>the</strong>size <strong>the</strong>m. These methods can be divided as physical and chemical processes according to <strong>the</strong> method applied to release carbon atoms from carbon- containing precursor molecules (Moisala, et al. 2003). Arc-discharge and laser-ablation methods are <strong>the</strong> physical methods, CVD is <strong>the</strong> chemical method (Moisala, et al. 2003). Each method has unique properties in terms <strong>of</strong> <strong>the</strong> results obtained, since <strong>the</strong>y have advantages or disadvantages as shown in Table 2.1, which are focused in this section. 9
Table 2.1. Advantages and disadvantages <strong>of</strong> three main techniques used for CNT growth. Method Arc-discharge Laser-ablation CVD Pioneer Iijima (1991) Guo et al. (1995) Yacaman et al. (1993) Kind <strong>of</strong> CNT MWNT SWNT Both Yields High Low High Advantages Disadvantages -<strong>the</strong> high growth rate -simple and inexpensive -expensive equipment -<strong>the</strong> large amount <strong>of</strong> energy consumed 2.3.1. Arc-Discharge Method -<strong>the</strong> conditions easily optimized - narrow diameter range -expensive equipment -high temperature production -<strong>the</strong> large amount <strong>of</strong> energy consumed -simple mechanism -low cost -low temperature production -growth control -aligned growth -impurity -high structural defects Arc-discharge method by which <strong>the</strong> CNTs have been produced by Iijima (Iijima 1991) is <strong>the</strong> most common and perhaps <strong>the</strong> easiest way (Journet and Bernier 1998) to produce CNTs, fullerenes and amorphous carbon (Bonard 2006). A typical illustration <strong>of</strong> an arc-discharge apparatus is shown in Figure 2.9. 10
Page 1 and 2: THE EFFECTS OF OXIDIZERS ON THE DIA
Page 3 and 4: ACKNOWLEDGEMENTS During my master <
Page 5 and 6: ÖZET KİMYASAL BUHAR BİRİKTİRME
Page 7 and 8: TABLE OF CONTENTS LIST OF FIGURES .
Page 9 and 10: LIST OF FIGURES Figure Page Figure
Page 11 and 12: Figure 5.12. The growths with CO2 (
Page 13 and 14: Figure 5.36. Raman spectra
Page 15 and 16: Table 5.12. The amounts of<
Page 17 and 18: first two methods, arc discharge an
Page 19 and 20: Graphite is the mo
Page 21 and 22: preferred nanotube type because <st
Page 23: Figure 2.7. An illustration <strong
Page 27 and 28: 2.3.2. The Laser-Ablation Method Th
Page 29 and 30: hydrocarbons (Cui, et al. 2003) wit
Page 31 and 32: 2.3.3.1.2. Thin Film Support Layer
Page 33 and 34: 2.4. Growth Mechanism of</s
Page 35 and 36: (Amama, et al. 2009, Hata, et al. 2
Page 37 and 38: that the small amo
Page 39 and 40: Figure 4.1. The Magnetron Sputterin
Page 41 and 42: the tube as <stron
Page 43 and 44: Table 4.1 (cont.) FeAlO15CNT840 750
Page 45 and 46: their diameter rou
Page 47 and 48: The principle of R
Page 49 and 50: Figure 4.6. Schematic picture showi
Page 51 and 52: 5.1.1. AFM Results There exists a p
Page 53 and 54: a ) Figure 5.2. AFM micrographs <st
Page 55 and 56: c Figure 5.3. (cont.) Element Wt %
Page 57 and 58: Table 5.2. (cont.) FeAlO12CNT771 76
Page 59 and 60: a b c e Figure 5.4. The growths wit
Page 61 and 62: Figure 5.5. (cont.) Count 35 30 25
Page 63 and 64: Due to the lack <s
Page 65 and 66: a c e Figure 5.8. The growths with
Page 69 and 70: Table 5.6 shows that the</s
Page 71 and 72: a c e Figure 5.12. The growths with
Page 75 and 76:
In this part, for the</stro
Page 77 and 78:
For FeAlO15 substrate, two differen
Page 79 and 80:
For FeAlO16 substrate, two differen
Page 81 and 82:
e f Figure 5.20. (cont.) Due to <st
Page 83 and 84:
5.2.1.3. CNT Formation at Different
Page 85 and 86:
Count 30 25 20 15 10 5 0 a 5 10 15
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Count 35 30 25 20 15 10 5 0 a CNT 8
Page 89 and 90:
Count 40 35 30 25 20 15 10 5 0 a CN
Page 91 and 92:
Count 45 40 35 30 25 20 15 10 5 0 a
Page 93 and 94:
Count 30 25 20 15 10 5 0 a 5 10 15
Page 95 and 96:
for SWNTs, there i
Page 97 and 98:
Table 5.17. (cont.) FeAlO15 CNT773
Page 99 and 100:
Intensity (a.u.) 2700 1800 900 CNT8
Page 101 and 102:
Intensity (a.u.) 2100 1400 700 CNT9
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whole face. The formed catalyst par
Page 105 and 106:
Diameter Diameter 10 8 6 4 2 0 5 5
Page 107 and 108:
5.4. Statistical Analysis Results A
Page 109 and 110:
Kurtosis value is a descriptor <str
Page 111 and 112:
Very thin Fe films were grown on Si
Page 113 and 114:
REFERENCES Amama, P.B., C.L. Pint,
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Hasegawa, K. and S. Noda. 2011a. Mi
Page 117 and 118:
Makita, Y., S. Suzuki, H. Kataura,
Page 119 and 120:
Vesselényi, I., K. Niesz, A. Siska
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