US Patent 7332736 - Sharpened nanowire electron emission arrays

http://www.freepatentsonline.com/7332736.html

One important consideration for nanowire/nanotube electron emission devices is the density of the nanowires used for emission. If the emitters are too close a field screening effect can reduce the efficiency of emission. This patent from Samsung teaches a sharpened tip nanowire array to improve the efficiency. Claim 1 reads:

1. An electron beam emitting source comprising: a gated field emission structure including an array of gated electron emission cells, each cell including an emitter support element, a gate electrode structure, a gate aperture and one or more nanowire electron emitters disposed on the support element and centrally positioned within the gate aperture, the total number of emitters in each cell limited to 10 or fewer, wherein each nanowire electron emitter is tapered from a thickest diameter portion to a sharp tip having a radius of curvature less than 1/10 of the thickest diameter.