Field emission microscopy of graphene on iridium point emitter

Bernatskii, D. P.; Pavlov, V. G.

doi:10.1134/s1063785011120182

Cited by 7 publications

(2 citation statements)

References 3 publications

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“…This interest is primarily due to the possibility of using these emitters as active ele ments in various ion and electro optical devices [1][2][3][4][5]. There is a general tendency toward the develop ment of technology for obtaining emitters operating at possibly low voltages, which is mostly ensured by reducing the radii of emitting points down to a nanometer level.…”

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High-field formation of multipoint field-electron emitters

et al. 2012

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In recent years, the wide use of vacuum nanoelec tronic devices has stimulated the development of high efficiency field emitters. This interest is primarily due to the possibility of using these emitters as active ele ments in various ion and electro optical devices [1][2][3][4][5]. There is a general tendency toward the develop ment of technology for obtaining emitters operating at possibly low voltages, which is mostly ensured by reducing the radii of emitting points down to a nanometer level. In order to obtain significant ion and electron currents, there is a general trend toward man ufacturing field emission sources with developed sur faces-in particular, multipoint emitters. The main difficulties encountered in the implementation of these sources are related to the nonuniformity of emis sion [6]. Because of the mutual local screening, the average current per emitter decreases with an increase in their number so that the total emission current is not proportional to this number in the array.The existing high field methods used for decreas ing the dispersion of local field factors in multipoint emitter arrays are based on self consistent variation of the curvature radius at the point vertex depending on the mutual screening factor [5]. However, the effi ciency of these methods is significantly limited by the probability of emitter fracture and electric breakdown in the course of field evaporation [7]. The present Let ter demonstrates that the probability of increasing the efficiency of formation of field induced emission sources with developed (multipoint) surfaces can be increased due to the phenomenon of evaporation in a strong electric field, which is additionally simulated by the presence of active gases [8].Experiments were performed in a two chamber field ion microscope capable of imaging the emitter surface in field ion microscopy (FIM) and field elec tron microscopy (FEM) regimes [9]. The images were obtained using a microchannel detector with a lumi nescent screen. The residual gas pressure in the work ing chamber was about 10 -6 Pa. In order to resolve the emission images of separate point emitters, electron beams were contracted by placing the multipoint array in a homogeneous magnetic field of 0.8-1.5 T. The emitters were formed by electrochemical etching in 1 N aqueous sodium hydroxide solution. The field emission source was assembled as a linear array of point emitters that were spot welded to a tantalum base plate at a 2 mm step. The heights of emitters were spread within ±1 mm. The initial radii of curvature at the point vertices were within 7-15 nm. The average spread of local field enhancement factors was in excess of 50%.In order to reduce the variance of the local field enhancement factors and form an atomically smooth surface of emitters, we have used the method of low temperature field evaporation [5] based on the expo nential dependence of the rate of material evaporation from the emitter point tip on the electric field strength. The local field enhancement factors in multipoint emitter...

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High-field formation of multipoint field-electron emitters

et al. 2012

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“…In [6] it was shown that, during cesium atom adsorption onto the surface of a carbonized iridium field emitter at the temperature of T = 300 K, cesium atoms can be located not only on the graphene surface, but also under the graphene layer as a result of intercalation. Both phases affect the work function.…”

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Modification of the emission surface of a carbonized iridium field emitter during the adsorption of barium atoms

Bernatskii

Pavlov

2022

Technical Physics Letters

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Field electron microscopy was used to study the modification of the emission surface of a carbonized iridium field emitter when the concentration of barium atoms on the surface changes within the monolayer coating. When barium atoms are adsorbed at a temperature of T=300 K, no significant changes in the field electronic images of the emission surface are observed. The formation of barium islands on graphene in the region of the (100) iridium face at the annealing temperature T=1200 K was detected. At the annealing temperature T=1500 K, the barium island is dissolved and graphene is intercalated by barium atoms. The emission surface increases and becomes uniform in emission. Keywords: field electron emission, carbon, iridium, intercalation, field emitters.

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