Electron field emission from undoped polycrystalline diamond particles synthesized by microwave-plasma chemical vapor deposition

Abstract

Electron field emission properties of nanodiamonds synthesized by the chemical vapor deposition process Electron emission characteristics of boron nitride films synthesized by plasma-assisted chemical vapor deposition J.Synthesis and electron field emission of nanocrystalline diamond thin films grown from N 2 /CH 4 microwave plasmas Electron emission from polycrystalline diamond particles (PDPs) was obtained at low electric fields in the absence of intentional doping. The PDPs were synthesized on a silicon substrate using microwave-plasma chemical vapor deposition accompanied by bias-enhanced nucleation. Polycrystalline diamond particles of two different sizes, i.e., $500 nm and 2 to 5 lm, were obtained, the surfaces of which were covered with small crystal grains composed of fine facets. Electron emission from the PDPs was characterized by Fowler-Nordheim tunneling with low turnon-field values (0.8 -2.0 V/lm) and a low barrier height of 0.02 eV. An emission current greater than 5 lA was maintained for over 24 h in a cathode based on the developed PDPs. In contrast, single-crystalline diamond particles prepared for comparative purposes exhibited no emission up to 2.5 V/lm. Auger electron spectroscopy revealed that the surface oxygen content modified by annealing in air did not affect the emission properties. The macroscopic spatial distribution of the emission spots was roughly consistent with the population density distribution of PDPs on the cathode. It is postulated that emission from the PDPs arises as a result of the small crystal grains on the surface and the presence of a sp 2 -bonded phase in the grain boundaries, which enabled strong field enhancement and carrier transport through the undoped diamond particles.

Field‐Induced Electron Emission from Nanoporous Carbons

“…We think that all these features of emission from NPC may be explained in terms of the two-stage model of emission mechanism [2,[17][18][19][20][21][22][23][24][25][26] with a few important modifications discussed below. According to this model, electrons are transferred from the emitter bulk electron states near Fermi level ( ) to vacuum not directly but in two successive steps via some (probably different for different materials) intermediate states localized near the emitter surface, with energies substantially higher than .…”

“…The phenomenon of low-field electron emission for such materials cannot be explained by the classical Fowler-Nordheim (FN) theory, so a few principally different emission models were proposed for them in the past years [7][8][9][10][11][12][13][14][15][16]. Most commonly, the models involve a multistage tunnel transfer of electrons via domains with different electronic properties [2,[17][18][19][20][21][22][23][24][25][26].…”

Fabrication of cone-shaped CNF/SiC-coated Si-nanocone composite structures and their excellent field emission performance

“…2(a) and 3(a). Earlier studies of diamond particles 26 and bamboo-like SiC nanowires 27 have demonstrated that nanostructures with fine facets may have ideally large curvatures and their sharp corners may serve as emitting centers as well. As a result, it is suggested that for our samples the existence of the faceted catalyst particles on the CNF top ends not only clearly indicates the tip growth mechanism for the CNFs, but also provides the sharp corners with extremely small radius of curvature, which may act as efficient electron emitting sites due to the strong local field enhancement at their surfaces, thereby greatly improving the FE efficiency.…”

Field-emission Properties of Ni-C Nanocomposite Films

“…Though, this approach also implies concentration of all destructing factors at the emitter tips, which limits its lifetime or extracted current or both. At the same time, the possibility to obtain low-field cold electron emission from geometrically smooth surfaces had been recently demonstrated with different nanostructured refractory materials, mostly nanocarbons [1][2][3][4][5][6][7][8][9]. The precise mechanism of the emission facilitation in many cases remains unclear, but it is usually associated with nanoscale heterogeneity of the efficient emitters [7][8][9].…”