Enhanced Cold Field Emission of Large-area Arrays of Vertically Aligned ZnO-nanotapers via Sharpening: Experiment and Theory

Abstract

Large-area arrays of vertically aligned ZnO-nanotapers with tailored taper angle and height are electrodeposited on planar Zn-plate via continuously tuning the Zn(NH3)4(NO3)2 concentration in the electrolyte. Experimental measurements reveal that the field-emission performance of the ZnO-nanotaper arrays is enhanced with the sharpness and height of the ZnO-nanotapers. Theoretically, the ZnO-nanotaper is simplified to a “charge disc” model, based on which the characteristic macroscopic field enhancement factor (γC) is quantified. The theoretically calculated γC values are in good agreement with the experimental ones measured from arrays of ZnO-nanotapers with a series of geometrical parameters. The ZnO-nanotaper arrays have promising potentials in field-emission. The electrochemical synthetic strategy we developed may be extended to nanotaper arrays of other materials that are amenable to electrodeposition, and the “charge disc” model can be used for quasi-one-dimensional field emitters of other materials with nano-sized diameters.

Nitrogen plasma formation through terahertz-induced ultrafast electron field emission

“…10(a) shows plots of lnI ∕E 2 av versus 1∕E av , where E av is the photon-averaged incident electric field. The time-domain field enhancement factor β can be calculated from the slopes of those plots [32,33]. The field enhancement factor in that calculation depends on the assumed height of the tunneling barrier Φ, and convincing agreement between experiment and numerical simulations is obtained for Φ 0.25 0.03 eV [ Fig.…”

Structure and electron field emission properties of ion beam reduced graphene oxide sheets

“…It is found that the ion irradiation significantly reduces threshold voltage of the GO emitter which might be due to the reduction of oxygen at the surface of GO sheets provided more field emission active sites. The field emission characteristics of pristine and irradiated GO sheets can be quantitatively explained using the modified FowlereNordheim (F-N) equation [30,31]. The field emission current can be expressed as:…”

The tunneling potential for field emission from nanotips

“…Common mechanisms for producing an electron beam are thermionic, field and photo emission. A topic of current research centres around large area arrays of pointed field emitters [7][8][9][10][11][12] that offer high brightness, high current density beams having a small spread in energy at low operational temperatures.…”