Field and explosive emissions from graphene-like structures

Dimensional Quantization and the Resonance Concept of the Low-Threshold Field Emission

“…The magnitude of the threshold measured in experiment (see [2,3]) is qV = (20 − 100) meV. These values of the threshold may be qualitatively explained based on resonance tunneling through the size-quantization level.…”

“…This completely classical explanation of the low -threshold emission phenomenon is not universal, and certainly non valid for carbon-covered cathodes. This has been considered in our recent papers [2,3,7] because the surface of the carbon flakes, obtained by the detonation synthesis are perfectly smooth with rare and relatively small protrusions. These protrusions are able to lower the threshold by a factor of 5, while a lowering factor of 10 2 is observed in our experiments.…”

“…In numerous recent experiments, see for instance [1][2][3][4][5][6][7][8], extremely low-threshold field emission from the carbon nano-clusters was observed for electric fields (10 4 − 10 5 V/cm). This is a surprisingly strong effect, because the field initiating a noticeable emission from these materials is 2-3 orders less than the field required for the field-emission from the traditional metals and semiconductors.…”

“…These protrusions are able to lower the threshold by a factor of 5, while a lowering factor of 10 2 is observed in our experiments. We suggested in [2,3,7] an alternative explanation of the threshold lowering (field enhancement) based on the dimensional quantization in the under-surface space-charge region on the metal-graphene interface. Recent experiments done by our group confirm the continuity of spectrum 2D-size quantization and allow us to estimate the effective mass m * and the de Broglie wavelength in space-charge region depending on electron's concentration n ex = 1 q τ 0 J(t)dt, where j = I/S, I = 80 A is the current and S ≈ 0.75 cm 2 -the area of the cathode, τ ≈ 2 × 10 −9 s. Monitoring of current density allows us to estimate the experimental density of charges Q = 2.4 × 10 −7 Coul/cm 2 , which corresponds to density of electrons n ≈ 1.3 × 10 12 cm −2 .…”

Features of full energy distribution from graphene like structures by the retarding potential method

“…It was shown [1] by direct experiments that excitation field emission structures on graphene-like structures occurs in electric fields by 2-3 orders lower than for metals and semiconductors. Studies [1] have shown that the mechanism of this low threshold issue may be related to the size quantization, the consequence of which has a resonant tunneling from graphene in a vacuum.…”