The image-charge correction for curved field emitters

Autor:	Rajasree Ramachandran, Debabrata Biswas
Rok vydání:	2017
Předmět:	010302 applied physics Physics Schottky effect Electron Condensed Matter Physics Method of image charges 01 natural sciences 010305 fluids & plasmas Radius of curvature (optics) Field electron emission 0103 physical sciences Rectangular potential barrier Atomic physics Hyperboloid Current density
Zdroj:	Physics of Plasmas. 24:073107
ISSN:	1089-7674 1070-664X
DOI:	10.1063/1.4990562
Popis:	The image-charge potential plays a key role in field emission by lowering the potential barrier, thereby leading to an increase in current density by orders of magnitude. The classical image-charge potential is however strictly applicable to planar emitters rather than the curved protrusions characteristic of field emission sites. Using recent results [Jensen et al., J. Vac. Sci. Technol. B 35, 02C101 (2017)] for a hyperboloid emitting surface, we show that for a charge close to the emitter surface, the image charge magnitude and location are well approximated by replacing the surface locally by a sphere having the same radius of curvature. Corrections to the image-charge potential under this approximation are calculated and found to be significant for field emission when the radius of curvature is in the nanometer regime. In such cases, there is reduced electron emission and the effect is more pronounced at lower external field strengths.
Databáze:	OpenAIRE
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