A three-dimensional model for thermionic emission from graphene and carbon nanotube
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IOP Publishing Ltd
Abstract
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Graphene and carbon nanotube (CNT) have been proposed to be good materials for thermionic
energy converter (TEC). For accurate simulation of performance of TEC, it is important to know the
correct equation for temperature dependence of thermionic emission current density (J) from
graphene and carbon nanotube. In this paper we first consider the existing theory of electron energy
dispersion relation in graphene to reconsider the relations between Fermi energy and Fermi velocity in
relation to some form of electron mass in graphene.Wethen consider existing various models of
temperature dependence of J versus T (J(T)) and their applicability to nano-materials.Wefind that no
model exists to date that fully conforms to the available experimental data on J(T) of nano materials.
By providing justifications for three components of electron momentum vector during thermionic
emission from graphene, we then find a three-dimensional model that fits the experimental
thermionic emission data from graphene and carbon nanotube far better than any existing model.We
present a detailed comparison of our model with existing models of thermionic emission. The work
function determined using our model also agrees very well with independent experimental results.
This model is expected to be very effective in modelling TEC with graphene or CNT.
Keywords
QC Physics