Year: 2005
Type: dissertation
Abstract: 1-D Nanostructures are attractive candidates for electron emitters in vacuum \nmicroelectronic devices because of their sharp tip radii and high aspect ratio. With \nadvances in nanotechnology, various strategies have been reported for controlled \nsynthesis of nanostructures including 1-D variants (nanowires and nanotubes). While \nvarious functional electronic/optoelectronic devices and circuits have been \ndemonstrated using nanostructures, this work is focused on the synthesis and field \nemission studies of 1-D nanostructures of three materials systems, namely carbon \nnanotubes, silicon nanowires and graphitic nanocones. The potential applications of \n1-D nanostructures as electron emitters are varied and include displays, microwave \namplifiers, x-ray sources, holography, multiple e-beam lithography, electronic \ncooling. The carbon nanotubes (CNTs) are grown in anodic alumina templates by \nthermal chemical vapor deposition (CVD). The Silicon Nanowires (Si NWs) are \ngrown by atmospheric pressure CVD (APCVD) via hydrogen reduction of silicon \ntetrachloride with an Au thin film acting as the catalyst for the Vapor-Liquid-Solid \n(VLS) process. Further post-growth processing was employed in the case of Si NWs, \nnamely in-situ annealing and cesiation, to improve the field emission characteristics. \nFinally, field emission characterization of individual tubular graphitic nanocones \n(TGCs) was carried out. The TGCs were grown on iron needle by microwave plasma \nassisted CVD of C2H2 + N2. An individual nanocone emitted a current as high as 80 \nµA, corresponding to a current density of ~ 108 \n A/cm2 \n, without breakdown. \nIndividual emitters would be of interest for applications in holography and as \ncoherent electron sources.
Author: Niraj Kulkarni
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1520520244