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My research
at NC State University |
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Growth and
characterization of GaN |
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I have started
my research at NC State with the growth and characterization
of GaN. |
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Growth was
performed utilizing molecular beam epitaxy (MBE). |
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Characterization was done by photoluminescence (PEL)
and capacitance/voltage measurements. |
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My research
at Arizona State University |
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Growth and
characterization of intrinsic and doped single crystal diamond. |
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Since 1998 I
have been working on carbon based materials, mainly doped
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nanocrystalline diamond and carbon nanotube
films. |
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Diamond
films are synthesized utilizing plasma assisted chemical
vapor deposition in an |
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AsTex IPX 3750
reactor. The plasma, mainly hydrogen, creates atomic species from |
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a carbon source (methane,
CH4) that can form a diamond crystal
structure on a hot |
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substrate, here, a single
crystal diamond plate. |
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Characterization includes field- and thermionic emission to
explore the potential in thermionic energy conversion. |
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Thermionic
energy conversion is a process where heat is transformed
into electricity. This process operates entirely in |
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the solid
state, i.e. without any moving parts, and with efficiencies
exceeding 50% possible. |
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Thermionic
energy converters were first used in space missions as a
reliably, low maintenance power source. However, |
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metal based
flat emitters required high temperatures up to 1900K and
were limited by space charge effects, where |
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electrons would
form a charge cloud adjacent to the emitter surface and prevent
electrons from being efficiently removed from |
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the cathode. As
a countermeasure, ionizing vapors were introduced that
reduced space charge effects and also resulted |
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in a reduction
of the work function of emitter and collector. |
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more... |
