tailieunhanh - Báo cáo hóa học: " Field Emission and Radial Distribution Function Studies of Fractal-like Amorphous Carbon Nanotips"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Field Emission and Radial Distribution Function Studies of Fractal-like Amorphous Carbon Nanotips | Nanoscale Res Lett 2009 4 431-436 DOI s11671-009-9270-5 NANO EXPRESS Field Emission and Radial Distribution Function Studies of Fractal-like Amorphous Carbon Nanotips F. Sola A. Biaggi-Labiosa L. F. Fonseca O. Resto M. Lebron-Colon M. A. Meador Received 30 September 2008 Accepted 28 January 2009 Published online 13 February 2009 to the authors 2009 Abstract The short-range order of individual fractal-like amorphous carbon nanotips was investigated by means of energy-filtered electron diffraction in a transmission electron microscope TEM . The nanostructures were grown in porous silicon substrates in situ within the TEM by the electron beam-induced deposition method. The structure factor S k and the reduced radial distribution function G r were calculated. From these calculations a bond angle of 124 was obtained which suggests a distorted graphitic structure. Field emission was obtained from individual nanostructures using two micromanipulators with subnanometer positioning resolution. A theoretical three-stage model that accounts for the geometry of the nanostructures provides a value for the field enhancement factor close to the one obtained experimentally from the Fowler-Nordheim law. Keywords Carbon nanotips Graphite-like a-C EeLs EFED Field emission Introduction Nanotips made of carbon can have many different applications such as scanning microscope probes 1 and F. Sola A. Biaggi-Labiosa L. F. Fonseca El O. Resto Department of Physics Institute for Functional Nanomaterials University of Puerto Rico Rio Piedras . Box 23343 San Juan PR 00931 USA e-mail M. Lebron-Colon M. A. Meador Polymeric Materials Branch Materials and Structures Division National Aeronautics and Space Administration Glenn Research Center 21000 Brookpark Road Cleveland OH 44135 USA field emission FE sources 2 . For instance recently carbon nanofibers were used as the electron source in order to test and build an FE display device prototype where a new .