Review on peculiar issues of field emission in vacuum nanoelectronic devices

Low-Field Electron Emission Capability of Thin Films on Flat Silicon Substrates: Experiments with Mo and General Model for Refractory Metals and Carbon

“…All these spectra include staircase-like features, which are usually associated with nanoparticles that have isolated electron systems. In literature, they are attributed either to dimensional quantization [14,57,74] or the Coulomb blockade effect [2,30,[75][76][77][78][79]. Thus, it can be inferred that at least some islets directly observed in microscopic images (Figures 7b, 8e and 9a) were insulated from their environment-as it is required by several emission models [2,[42][43][44][49][50][51][52][53][54][55][56][57], including the model proposed in [62].…”

“…Alternative emission mechanisms (different from direct electron tunneling via a single surface barrier) suggested for ENH carbon species [14,[42][43][44][45][51][52][53][54][55][56][57][58][59] often associate the LMF emissivity with nanoscale heterogeneity. Internal boundaries and high gradients of physical parameters produce favorable conditions for emission facilitation via local field enhancement, generation of hot carriers, resonance, quantum size effects, etc.…”

“…However, the concentration of the electric field at the high-aspect-ratio surface features also implies the concentration of destructive factors such as ion sputtering, Joule heating, and ponderomotive forces. Consequently, long-term stability and lifetime remain among the key issues for cold cathodes with sharp emitting tips, which brings into attention planar or smooth-surface cold emitters as competitive options [2,6,11,14].…”

“…The LMF emission capability is known to be inherent in various electrically nanostructured heterogeneous (ENH, [42]) carbon species, such as diamond or diamond-like films, nanographites, and sp 2 /sp 3 composites [2, [42][43][44][45][46][47][48][49][50][51][52], even in the absence of visible sharp protrusions of the outer boundary. Very different models [14,[42][43][44][45][51][52][53][54][55][56][57][58] were proposed to explain this phenomenon. Many of them were based on the assumption of the field penetration into the emitter or/and its enhancement at internal conductive structures, such as particles of sp 2 -bonded carbon, grain boundaries, or electroformed current channels.…”

Wigner wave packets: Transmission, reflection, and tunneling

“…Processes associated with the field emission of electrons operate on disparate length scales that span many orders of magnitude [1][2][3]. Tunneling is exquisitely sensitive to the barrier shape [4][5][6], which in turn depends on microscale surface curvature [7][8][9][10][11][12], emitter shape [13][14][15], surface roughness [16][17][18][19][20][21][22] and nearest neighbor (shielding) effects in arrays [23][24][25]. Simulating emission using, for example, particle-in-cell (PIC) or molecular dynamics codes is already challenging because of the difficulty in reconciling particle transport with tunneling (wave) behavior [17,[26][27][28].…”