[Seminars] SPECIAL SEMINAR TODAY

[Ramona Echols]

    **SPECIAL CBB SEMINAR TODAY **
    
    3:10 PM PRC 201
    
    Speaker: Sergey Baryshev, Michigan State University 
    
    Title: Quantum Effects in Electron Emission from Nanodiamond

    Abstract: 
Synthetic granular ultra-nano-crystal line diamond with a high n-type conductivity
via nitrogen doping ((N)UNCD) has emerged as a high efficiency field- or photo-emission
source. It is widely anticipated that graphitic grain boundaries (surrounding diamond
grains) are behind the high efficiency of (N)UNCD. Grain boundary effect hypotheses rest
upon the fact that (N)UNCD efficiency can be largely "tuned" through the diamond-to-graphite
ratio typically quantified by optical and X-ray spectroscopy techniques.
In this talk, some unconventional effects that assist electron emission from
(N)UNCD will be outlined: 1) output current saturation and 2) light emission during field
emission, and 3) intrinsic emittance independent of the excess photon energy during
photoemission. Our recent experimental and theoretical works, which further corroborate
the crucial role of defect grain boundary states on electron emission from (N)UNCD, will
be summarized. We will outline the critical role of density of grain boundary states
induced inside the diamond fundamental band gap, charge carrier mobility and effective
mass, as well as grain boundary spatial effects on electron emission. It will be discussed
how the models, implying quantum effects associated with the graphitic grain-boundary-promoted
electron emission, can simultaneously and self-consistently account for high
efficiency and unconventional behavior of (N)UNCD.

    
    Warmly, 
     
    Ramona Echols,  EFI/HEP Secretary IV
    Enrico Fermi Institute 
    University of Chicago
    933 E 56th Street, PRC 101
    Chicago, IL 60637
    Phone: 773-702-8113
    Rechols06 at uchicago.edu
     
     
    
    

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