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​Vertically aligned graphene edges at pencil lead apex as efficient field electron emitters 

Researchers at University of Tsukuba have demonstrated that graphitizing the apex of a mechanical pencil lead (PL) produces vertically aligned graphene edges that function as efficient electron emission sources. Due to their pointed morphology, these graphene edges enabled stable field emission at relatively small macroscopic electric fields of several V/µm, without the need for an ultra-high vacuum environment.

Field emission microscopy revealed the distinctive “dragonfly pattern” characteristic of graphene edge emission, confirming the nearly vertical alignment of graphene flakes at the apex of PL. Analysis of the energy spectrum of emitted electrons showed a distribution slightly broader than that of metals, reflecting the density of states of graphene’s π-bands. This observation was further supported by recursion-transfer-matrix simulations.

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Researchers at University of Tsukuba have demonstrated that graphitizing the apex of a mechanical pencil lead (PL) produces vertically aligned graphene edges that function as efficient electron emission sources. Due to their pointed morphology, these graphene edges enabled stable field emission at relatively small macroscopic electric fields of several V/µm, without the need for an ultra-high vacuum environment.Field emission microscopy revealed the distinctive “dragonfly pattern” characteristic of graphene edge emission, confirming the nearly vertical alignment of graphene flakes at the apex of PL. Analysis of the energy spectrum of emitted electrons showed a distribution slightly broader than that of metals, reflecting the density of states of graphene’s π-bands. This observation was further supported by recursion-transfer-matrix simulations. 

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