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

0

20

40

60

80

100

120

0 5 10 15 20

Fermi level, IEFI

IEfI = 622.14 -1

Ferm

i lev

el, I

EFI (

meV

)

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