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Table of Contents
Dedication .......................................................................................................................... iii Acknowledgments.............................................................................................................. iv Table of Contents ............................................................................................................... vi List of Figures ..................................................................................................................... x List of Tables.................................................................................................................... xiv
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List of Figures
Figure 1-1, Typical mass spectrum of sooting discharge obtained using ExB Velocity Filter, counts on y - axis and Voltage across plates on x- axis........................................ 5 Figure 1 - 2, Model of C 60 docked in the binding site of HIV - 1 protease [6]....................... 8 Figure 1-3, AFM image of the fabricated multiwalled nanotube device.The lower tube has gold contacts at both ends, while the upper tube has only one end contacted [7]. 9 Figure 1 - 4, Nanotube Single - Electron Transistor Working at room temperature [8]......... 9 Figure 1-5, Some of the computer modeled examples of Nano Electro Mechanical Systems [10]. .............................................................................................................. 10 Figure 2 - 1, Percentage ionization as a function of temperature for different atom densities of hydrogen [26]. ........................................................................................................ 16 Figure 2 - 2, Schematic diagram of Plasma Dischar ge Tube [26]. ..................................... 16 Figure 2-3, Schematic diagram of International Thermonuclear Experimental Reactor [17]. ............................................................................................................................ 18 Figure 2 - 4, Schematic Diagram of Joint European Torus [18]. ........................................ 18 Figure 2-5, Pictures of MFTF-B Reactor at Lawrence Livermore National Laboratory [27,19]. ....................................................................................................................... 19 Figure 2 - 6, Diagram of National Ignition Facility [17]. ................................................... 19 Figure 2-7, 7Schematic diagrams showing various configurations of MHD Power Systems [28]. .............................................................................................................. 20 Figure 2 - 8, I- V Curve showing various stages of discharge [26]. .................................... 21 Figure 2 - 9, Schematic diagram of various spatial regions in glow discharge [26]........... 23 Figure 2-10, Population Inversion, i.e. atomic energy levels fails to follow Boltzmann Distribution [29]. ........................................................................................................ 24 Figure 2 - 11, Four Level Population Inversion in Typical LASERs. ................................ 25 Figure 3 - 1, Schematic diagram of Single Probe inserted into plasma [26]....................... 29 Figure 3 - 2, I- V Curve of Single Probe [26]. ..................................................................... 30 Figure 3 - 3, Schematic diagram of Double Probe [26]. ..................................................... 31 Figure 3 - 4, I- V Curve of Double Probe [26]..................................................................... 31 Figure 3 - 5, Schematic diagram of magnetic coil [26]....................................................... 31 Figure 3 - 6, Schematic diagram of Flux loop [26]............................................................. 32 Figure 3 - 7, Schematic diagram of Rogowski coil [26]. .................................................... 32 Figure 3 - 8, Singlet and triplet energy levels of C 2 molecule [30]..................................... 34 Figure 4-1, STM image showing iron atoms adsorb on a copper (111) surface forming a "quantum corral" at a very low temperature (4K) [38]. ............................................. 37 Figure 4-2, IBM s Logo Nanofabricated with Xenon Atoms on Nickel Surface with STM [3]. .............................................................................................................................. 38 Figure 4 - 3, Schematic diagram of th e Scanning Tunneling Microscope [38]. ................. 41 Figure 4 - 4, Basic Setup for Scanning Tunneling Microscopy [38]. ................................. 41 Figure 4 - 5, A Typical STM Image [38]. ........................................................................... 42 Figure 4-6, Overview of various atomic manipulation methods available using STM [40]. .................................................................................................................................... 43
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Figure 8 - 15, Baseline detection from the peaks of March experiment. ............................ 98 Figure 8-16, Level densities as a function of time of one of the data acquisition during March Experiments. ................................................................................................... 99 Figure 8-17, Population Inversion Parameter as a function of time of one of the data acquisition during March Experiments, possible population inversion the plasma at NLTE and excitation temperature could not be calculated. ....................................... 99 Figure 8-18, 473 and 516 nm C 2 peaks of one of the set of data acquisition from 23rd June experiments super imposed on a single plot. .................................................... 101 Figure 8 - 19, Baseline detection from the peaks of 23 rd^ June experiments. .................... 102 Figure 8-20, Level densities as a function of time of one of the data acquisition during 23 rd^ June Experiments. ............................................................................................. 103 Figure 8-21, Population Inversion Parameter as a function of time of one of the data acquisition during 23 rd^ June Experiments. .............................................................. 10 4 Figure 8-22, Excitation Temperature as a function of time of one of the data acquisition during 23 rd^ June Experiments.................................................................................. 104 Figure 9-1, Schematic diagram of a typical duoplasmatron used to create ionized species. .................................................................................................................................. 106 Figure 10 - 1, 10 C 2 mol ecules joined together to form C 20 .............................................. 114 Figure 10 - 2, Three views of Molecular Mechanics Modeled C 20 ................................... 115 Figure 10 - 3, Four views of Molecular Mechanics Modeled C 60 ..................................... 116 Figure 10 - 4, C 60 - arm - chair and C 60 -reduced- arm - chair caps joining to form C 70. ......... 117 Figure 10 - 5, Two views of Molecular Mechanics Modeled C 70 ..................................... 118 Figure 10 - 6, Two C 60 - zig - zag caps joining to form C 78 ................................................. 118 Figure 10 - 7, Two views of Molecular Mechanics Modeled C 78 ..................................... 119 Figure 10 - 8, Two C 60 - arm -chair caps joining to form C 80 .............................................. 120 Figure 10 - 9, Two views of Molecular Mechanics Modeled C 80 ..................................... 120 Figure 10-10, Two C 60 - arm -chair caps and 5 C 2 molecules joining together to form C 90. .................................................................................................................................. 121 Figure 10 - 11, Two views of Molecular Mechanics Modeled C 90 ................................... 122 Figure 10 - 12, Graphene, a sheet of Graphite. ................................................................. 122 Figure 10 - 13, Illustration of Unit Vectors that define Chiral Vector.............................. 123 Figure 10 - 14, Arm Chair Type Carbon Nanotube. ......................................................... 124 Figure 10 - 15, Zig Zag Type Carbon Nanotube............................................................... 124 Figure 10 - 16, Hybridization in Nitrogen. ....................................................................... 126 Figure 10-17, Comparison of N 60 geometry modeled at LLNL and PINSTECH for sp^3 and sp 2 hybridizations............................................................................................... 128 Figure 11 -1, Screen shot of the software developed for Computational Diagnostics..... 133 Figure 11 - 2, Baseline correction algorithm in Origin 6.1. .............................................. 134 Figur e 11 - 3, Baseline correction algorithm 1.................................................................. 135 Figure 11 - 4, Improved Baseline Correction Algorithm. ................................................. 136 Figure 11 - 5, Original Peak. ............................................................................................. 137 Figure 11 - 6, B - spline curve fitted to the peak................................................................. 137 Figure 11 - 7, Spectrum split in two halves....................................................................... 138 Figure 11 - 8, First and Second Derivative. ...................................................................... 138 Figure 11-9, Peak baseline identified and fitted with straight line by Improved Baseline Correction Algorithm 2. ........................................................................................... 139
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Figure 12-1, Calibration curve of HR2B454 Spectrometer obtained using OOIrrad Software.................................................................................................................... 144 Figure 12-2, Calibrated spectra of DH-2000 at 3msec. Integration time, 5 boxcar and 1 scan to average. ........................................................................................................ 145 Figure 12-3, Calibrated spectra of LS-450 at 1000msec. Integration time, 5 boxcar and 1 scan to average. ........................................................................................................ 146 Figure 12-4, Calibration of LS1-CAL and comparison with LS1-CAL calibration file, OOIrrad Calibration and Manual Calculations......................................................... 146 Figure 12-5, Counts and Irradiance of LS1-CAL connected to HR2B454 Spectrometer via Ultra Low OH and High OH Fiber Optic Cable s. .............................................. 147 Figure 12 - 6, Attenuation curves of High OH and Ultra Low OH Fibers [46]................ 147 Figure 12-7, Linear attenuation curves of Fiber optic attenuator as supplied by OceanOptics Inc [46]................................................................................................ 149 Figure 12 - 8, Attenuator calibration curves using three light sources LS1 - CAL, LS450 and DH2000. ................................................................................................................... 151 Figure 12-9, Calibration surface for Attenuator connected with LS1-CAL via Low OH Fiber.......................................................................................................................... 152 Figure 12-10, Calibration surface for Attenuator connected with LS1-CAL via High OH Fiber.......................................................................................................................... 152 Figure 12-11, Calibration surface for Attenuator connected with DH2000 at maximum power via High OH Fiber. ........................................................................................ 153 Figure 12-12, Calibration surface for Attenuator connected with LS450 via Low OH Fiber.......................................................................................................................... 153 Figure 12-13, Calibration surface for Attenuator connected with LS450 via High OH Fiber.......................................................................................................................... 154 Figure 12 - 14, Mercury peaks obtained using CbN2 and CbN3 spectrometers............... 155
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Abstract
Carbon based Nano Technology, is a new cutting edge area of research related with
production of nano-scopic carbon molecules. This current project is part of an ongoing
research related with Carbon based Nanotechnology, sponsored by MOST at Electronics
Division, PINSTECH. The activity during this project is primarily focused on the
development and improvements in plasma diagnostic techniques with have fast time
resolution. Around 5 sets of experiments were performed during the research and optical
spectroscopy of C 2 molecule was the main diagnostic technique, to study fragmentation
and formation of carbon clusters. C 2 is suspected to play a vital role during fragmentation
and formation of carbon clusters. The problems in initial experiments were identified.
Additionally, all spectroscopy equipment was calibrated and newly bought equipment
was installed. A total of 4 ion sources were designed and fabricated, which were our main
setups for carbon cluster generation. Improvement in the vacuum equipment was also
carried out. In this pursuit of the improvements of experiments and data acquisition new
software were developed named NanoCPAPlasmaDiag and NanoCPACalibrate, with
Visual Basic 6.0 on front-end and Matlab 6.5 on the back-end. So we developed our
inhouse capability of equipment calibration, instead of getting services from OceanOptics
Inc. USA. Additionally, in order to extend our vision of phenomena responsible for
fullerene synthesis we carried out molecular simulation (molecular mechanics and
quantum mechanics) using ArgusLab code to model various close caged carbon carbon
clusters including fullerenes and nanotubes, and electrostatic simulations in ANSYS
Multiphysics to identify the electromagnetic fields developed in the ion sources used for
the experiments.
Section 1 - Introduction
including the attenuation effects of optics, CCD, grating, etc. Initially software supplied
by OceanOptics Inc. (manufacturer of spectrometers) was used, but it performed badly,
both in terms of execution and flexibility for our experiments. So we developed a new
software named NanoCPACalibration, again using VB6.0 and Matlab 6.5.
1.1.3 Computer Model ing and Simulations
On a parallel front, to extend our vision of phenomena responsible for fullerene synthesis
we carried out molecular simulation (molecular mechanics and quantum mechanics)
using ArgusLab code to model various fullerenes and electrostatic simulations in ANSYS
Multiphysics to identify the electromagnetic fields developed in the ion sources used for
fullerene synthesis. So we were able to model C 20 , C 60 , C 70 , C 78 , C 80 , C 90 , Armchair CNT
and Zig-zag CNT. We also modeled nitrogen based fullere nes like N 20 , N 60 , N 70 , N 78 , N (^80)
and N 90 , due to renewed interest of American researchers for nitrogen fullerenes in their
application as explosives. However, any attempt for nitrogen fullerene synthesis is
premature at this stage.
1.2 Motivation
1.2.1 Nano Technolo gy
The idea of nano technology evolved out of currently available human knowledge in a
motivation to develop a technology, which will be able to turn all human dreams into
reality, during 1980 s [ 1]. As Dr. Eric K. Drexler said in one of his books that :
Assemblers will let us build almost anything that the laws of nature allow to exist
[2].
Eventually, assemblers will allow engineers to make whatever can be designed,
sidestepping the traditional problems of materials & fabrication [ 2].
Initially scientists, rather philosophers, thought to re-evolve a new race of microscopic
machines in competition to existing life on Earth and this has been a center of much of
the debate. However, most were not even convinced that such a technology would ever
exi st. But in 1983 a discovery or rather an accident at IBM labs [3 ] convinced most of the
researchers of that time that such technology may someday exist, that is using Scanning
Tunneling Microscope scientists can pick single atom from one place and place it some
where else, i.e. atomic rearrangement can be carried out.
Advances in the technologies of medicine, space, computation & production and
warfare all depend on our ability to arrange atoms [ 2].
Almost at the parallel end some other scientists working on a completely different aspect
of science discovered bucky balls [4], perhaps the smallest building blocks of the future
micro machines. These bucky balls lead researchers to concentrate on this area and in just
a few years a whole lot of carbon clusters were discovered. Amongst them the most
popular ones other than bucky balls were carbon nano tubes [ 5].
1.2.2 Time Resolved Plasma Diagnostics
Currently there exist a number of techniques for the production of carbon clusters, like
laser ablation, ion sputtering, etc. In most of the techniques carbon-based plasma is
formed in which carbon atoms undergo a unique sequence of reactions leading to the
formation of larger molecules and eventually carbon clusters. It is proposed that the main
contributing molecule is C 2 in this formation of clusters from a smaller size to very large
clusters like carbon nano tubes. A thorough understanding of this formation mechanism
requires us to see C 2 at very fast rates, as these cluster formation reactions completes in
just a fraction of seconds. So the need of time resolved plasma diagnostics arose. The
main motivation behind this project is to explore very fast time resolved diagnostic
techniques and apply them to ongoing experiments related with the formation of clusters.
1.3 Re search Objectives
The main object of the project is to probe the plasma formed during cluster growth
mechanisms using various time resolved plasma diagnostics. This project is part of an
ongoing research at PINSTECH directed towards the identification of the physics of
1.4 Applications of Carbon Clusters
1.4.1 Buck y Balls
1.4.1.1 High Temperature Super Conductivity
This has been and still is one of the most important area of research in solid - state physics.
Applications, like Fusion Technology, desperately require super-conducting materials to
create large amounts of magnetic fields, yet can survive at normal temperatures. During
the research on electronic behavior of carbon-nanotubes it was found with the change in
diameter of the tube its electronic behavior transforms from metallic to semi-conductor,
further studies revealed that it is the chirality of the tubes which controls the electronic
behavior of nanotubes with the need of doping. At yet another front, researchers are
working on endohedral bucky balls, bucky balls with some atom or molecule trapped in
between them. Researchers have obtained indications that such endohedral bucky balls
with some particular hydrocarbons trapped inside them could lead to high temperature
super - conductors, which us humans have not obtained in the past.
1.4.1.2 Medical Radioisotope Treatment
Medi cal radioisotope treatment has been quite affective for the treatment of diseases like
cancer, etc. But the main problem is that the radioisotopes injected into the body after
serving their purpose, become part of the body and keep the patient exposed to r adiation
for long periods of time. One particular problem is that radioactive iodine, which is used
quite commonly in nuclear medicine, most of the times end up in thyroid gland and
eventually leads to thyroid cancer. One area of research related with carbon based
nanotechnology is attempting to solve such problems. Scientists are trying to trap
radioactive isotopes inside carbon cages, bucky balls, once injected into the body, the
body will consider them as carbon particles and will treat them accordingly. Thus solving
the problem of iodine going into thyroid gland.
1.4.1.3 Colored Medical Diagnostics
Yet, another area of application of carbon based nanotechnology, is to trap not one but
three nuclei or atoms inside a carbon cage, the bucky ball. The three atoms a re so selected
that they emit gamma-rays of three different wavelengths. Such radioactive species if
injected inside the body for medical diagnostics, could enable doctors to carry out colored
medical diagnostics. That is by treating the three wavelengths of gamma-rays as three
colors one could be enabled to get colored diagnostic images of various body parts.
1.4.1.4 HIV Treatment
In another area of work with buckyballs, a derivative of C 60 was shown to inhibit HIV-
and HIV-2, the human immunodeficiency viruses that cause AIDS (Acquired Immune
Deficiency Syndrome). Researchers at the University of California, San Francisco,
noticed that buckyballs fit perfectly into the active site of HIV protease, as shown in
Figure 1-2. The active site is where the reactions occur, if the active site is blocked the
virus is rendered ineffective. A water soluble derivative of C 60 was made by Fred Wuhl
and co-workers at University of California, Santa Barbara, and his compound was indeed
shown to disarm HIV virus and block HIV protease from cutting proteins. Unfortunately,
the potency of the buckyball analog is low when compared to AZT and other HIV
enzyme - inhibiting drugs.
1.4.2 Carbon Nano Tube
1.4.2.1 Single Electron Devices
Carbon nanotubes, exhibit a varied electronic behavior from metallic to semi- conducting,
without any addition of doping agents, simply based upon their chirality. It is thus
possible to fabricate very small carbon nanotubes into a device, like a transistor, which
can switch on / off with just few electrons, one such device made from two carbon
nanotubes placed between three gold contacts is presented in Figure 1-3, yet another
design utilizing kinked carbon nanotube is presented in Figure 1-4. This kind of research
has been on the way at many of the laboratories all around the World and some initial
success has occurred.
F igure 1-3 , AF M image of the fabricated multiwalled nanotube device.The lower tube has gold contacts at both ends, while the upper tube has only one end contacted [ 7].
Figure 1-4 , Nanotube Single - Electron Transistor Working at room temperature [ 8].
1.4.2.2 Nano Electro Mechanical Systems
The carbon nanotubes, bucky balls and other fullerenes will eventually be used to make
nanoscopic electromechanical machines, some of the possible designs modeled
computationally are presented in Figure 1-5. They will be used as the parts of the larger
machines like universal assemblers, swarms, etc. This will only be possible if we are able
to handle these nanoscopic clusters one by one and arrange them at atomic precision.
Research is on, but so far a faster and cost effective way to handling these clusters have
not been commercialized. Some organizations like Zyvex Corporation are marketing
equipment which can handle and manipulate nanotubes, but they are very slow,
expensive and not very flexible to handle each and every type of nanotube, but they are
working on it [ 9].
Figure 1-5 , Some of the computer modeled examples of Nano Electro Mechanical Systems [ 10 ].
Other applications of nanotubes include:
Nano structures, machines and MEMS [11].
High strength fibers [12 ].
