Talk by Dr. K. J. Sankaran on "Ultrananocrystalline Diamond Hybrids for Electron Emission Applications" | Shiv Nadar University
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Talk by Dr. K. J. Sankaran on "Ultrananocrystalline Diamond Hybrids for Electron Emission Applications"

Research
04 Oct 2018

Electrons from cold cathode emitters are usually obtained by applying an electric field, which tunnels the electrons from the material surface into vacuum. A cold cathode emitter is expected to possess certain characteristics, namely, resistance against chemical attack and ion bombardment by residual gases, sustaining plasma discharges, and stability in various gas environments. Other than the low onset fields, the long-lasting stability and stable emission current with very little/no fluctuations are necessary for using cold cathode materials in field emission displays (FEDs). Among field emitting materials, diamond owns excellent physical as well as chemical properties such as good thermal conductivity, tunable negative electron affinity, high secondary electron emission coefficient, high hardness, high chemical inertness, and wide band gap. All these characteristics render diamond materials as a promising candidate for application as cathodes in FEDs and plasma displays.

Here we present the enhancement of field electron emission and plasma illumination of ultrananocrystalline diamond (UNCD) hybrids employing different approaches like doping in the plasma, ion implantation and combination of UNCD with other nanocarbon materials. From our studies we reveal that such modifications of properties are related to microstructural alterations. The prominent change observed, and contributing to this enhancement, is the increase in the grain boundaries, with sp2 graphitic phases residing in them. The effect of n- or p-type doping into diamond is ruled out. The betterment of the electrical conductivity and field electron emission is attributed to the interconnected sp2 phases within the grain boundaries, which form itineraries for electrons to traverse through the material.

 

Speaker:  K. J. Sankaran

Institute for Materials Research (IMO), Hasselt University, Belgium.

IMEC vzw, IMOMEC, Belgium.

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