New carbon cone nanotip for use in a highly coherent cold field emission electron microscope

Abstract

A new cathode for cold-field emission gun using a pyrolytic carbon-cone supported onto a carbon nanotube as the electron emitting tip has been developped. This tip was mounted in a TEM using a FIB based method, and the brightness measured under real operating conditions is 5 times better than obtained with a standard tungsten tip. Its use overcomes the many technical difficulties which have dogged the use of carbon nanotube-based tips as proposed replacements for tungsten tips. The resulting properties of the final CFEG exhibit a very good energy spread of 0.32eV, a reduced brightness of 1.6×10 9 A.m-2 .sr-1 .V-1 and a very good long-term stability with a current damping less than 16% per hour.

Development of TEM and SEM high brightness electron guns using cold-field emission from a carbon nanotip

“…2 and described in detail by Houdellier et al in [22]. A standard tungsten FE tip and a preparation of several CCnT-bearing objects are loaded in the FIB.…”

“…The tip has been mounted using the FIB procedure described before and reported in [22]. The final picture of one tip mounted on a standard Hitachi tungsten tip is reported in Fig.…”

Ultrafast laser-induced field emission from a single carbon nanotube based nanotip

“…Investigations of the thermal response of the illumination are also studied for a variety of parameters. Our new experimental setup extends upon studies performed on conventional tungsten or gold tips, by using a new innovative tip based on a single carbon nanotube [7,8]. This recently developed nanotip raises high expectations for advances by implementation in electron microscopy [7].…”

“…Our new experimental setup extends upon studies performed on conventional tungsten or gold tips, by using a new innovative tip based on a single carbon nanotube [7,8]. This recently developed nanotip raises high expectations for advances by implementation in electron microscopy [7]. The carbon cone is grown onto a single multi-wall carbon nanotube (CNT) with an apex diameter of a few nm, and mounted on a tungsten tip with a focused ion beam, as shown in the inset of Fig.…”

Dielectric response of pentagonal defects in multilayer graphene nano-cones

“…4,5 While this has yet to be conrmed experimentally for either single-layer graphene or graphene nano-cones, 6 cold eld (CF) emission has recently been demonstrated in a working device for a cone-shaped carbon lament, which exhibits properties (such as brightness, current stability and spatial coherence) clearly exceeding those of traditional tungsten CF emitters. 7 In the simplest case, a topological defect in graphene consists of a single pentagon or heptagon incorporated in the hexagonal lattice. More complex defects can be formed by combining pentagons and heptagons into defect pairs.…”