MODEL CALCULATION OF THE SCANNED FIELD ENHANCEMENT FACTOR OF HEMISPHERICAL CNT TIP

Abstract

To examine the field enhancement factor for conducting hemispherical carbon nanotube (CNT) tip between two parallel plates. Hemispherical CNT tip is more realistic than floating sphere. To get the more accurate value of field emission and the screening effect of the cluster of hemispherical CNTs tip, the electrostatic potential for hemispherical CNT has been derived. Using mirror image method as Ahmed et al.[5] and Wang et al. have used to calculate field enhancement factor and screening effect of array of CNTs by considering floating sphere for any positional distribution of CNTs. The nature of electrostatic potential decreases with increase in radial distance as a point charge. We have derived an expression for field enhancement factor for individual hemispherical CNT tip. The screening effect for cluster of CNTs for any positional distribution dependence on the length of the CNT and the spacing between the CNTs is shown. Then compare the proposed model with experimental result of CNT with hemispherical tip.