University of South C arolina
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Transcript of University of South C arolina
University of South CarolinaSilicon Carbide Laboratory
EE RESEARCH - Dr. MVS Chandrashekhar-Epitaxial Graphene for Clean Energy
“Weightless” behavior of matter & Other Exotic Physics
Nanoelectronics and plasmonics for Computing & power using Graphene and SiC
Emissions Sensing, Monitoring & Controls Using SiC and Graphene
Electrochemistry of Epitaxial Graphene -Advanced functionality & Catalysis -Hydrogen storage, CO2 remediation
If I was an
electron?
University of South CarolinaSilicon Carbide Laboratory
EE RESEARCH - Dr. MVS Chandrashekhar-Epitaxial Graphene for Clean Energy
Conductivity, work function and reflectivity of graphene change in response to combustion emissions NO2, CO• Potential for single molecule sensitivity• Commercializable material platform-SiC substrates• Dramatically different physics than traditional materials
Energy Applications of Epitaxial Graphene
Electrochemistry using epitaxially grown EG on SiC substrates to produce advanced graphene Compounds for electronic and optical applications• TUNABLE Bandgap 0-3.5eV! Post-CMOS• Study H2 storage-SiC substrate changes chemistry• Study other electrochemical reactions
Si-f
ace`
Graphene Graphane
RMS: 1.04nm
C-f
ace RMS:
2.83nmRMS: 1.62nm
RMS: 0.57nm
RMS: 1.00nm
ResistanceGraphene ~9 kΩGraphane >40 MΩ
4 hour anneal ~100 kΩ
50 hour anneal ~21 kΩ
Distribution Statement
Plasmons & Polaritons in Epitaxial Graphene on SiC for Electrically Actuated Advanced Nanophotonics
Scientific/Technical Impact:• Fundamental insight into how plasmons can be
converted into an electrical current and vice-versa• Structure & Composition both matter.
• EG/SiC metamaterials approach overcomes diffraction limit of light by>10x.
• First systematic experimental investigation of polaritons in EG/SiC, a high impact material system
• Enable new paradigms in light generation.• Make practical compact plasmonic devices that
currently require bulky spectrometers.Key Insight/Innovation
Potential Applications:•>THz speed, compact computing•Compact plasmonic sensors
•Bioagents, chemical agents, infrared • Ionizing radiation
•Infrared and terahertz light sources •sensing & imaging for munitions
Backgate to actuatebetween plasmon waveguide & detector modes
University of South CarolinaSilicon Carbide Laboratory
EE RESEARCH - Dr. MVS Chandrashekhar-Epitaxial Graphene for Clean Energy
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Fermi level, IEFI
IEfI = 622.14 -1
Ferm
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EFI (
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Scattering time, (fs)
University of South CarolinaSilicon Carbide Laboratory
Plasmonic Effects in Epitaxial Graphene
λ0= electromagnetic excitation wavelengthλSPP= surface plasmon polariton wavelength λSPP< λ0 opens a new area of nanoscaled optoelectronics overcomes diffraction limit
~2ML thick graphene
Bare SiC substrate
Polariton in graphene
With adsorption of emissions gases for constant thickness reflectivity changes ~20% for 10ppm NO2
-Nonideality! Surface charged impurity scattering!-Enables probing of the nanoscale opto-physics of EG
Ideal gaphene has constant conductivity per MLi.e. reflectivity is only dependent on thickness outside restrahlen band
Fit to theory givesa) Thickness of EGb) Electron scattering timec) Carrier concentration in EG
EE RESEARCH - Dr. MVS Chandrashekhar-Epitaxial Graphene for Clean Energy