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Título : Fabrication of ultra-sharp tips from carbon fiber for scanning tunneling microscopy investigations of epitaxial graphene on 6H-SiC(0001) surface
Autor : Morán Meza, J. A.
Lubin, C.
Thoyer, F.
Villegas Rosales, K. A.
Gutarra Espinoza, A. A.
Martin, F.
Cousty, J.
Palabras clave : Carbon fiber (CF);Scanning tunneling microscopy (STM);Frequency modulation atomic force microscopy (FM-AFM)
Fecha de publicación : may-2015
Editorial : Elsevier Ltd
URI Relacionado: http://www.sciencedirect.com/science/article/pii/S0008622315000755
Resumen : The fabrication of ultra-sharp tips from carbon fiber (CF), which are mounted on a qPlus probe for combined dynamic scanning tunneling microscopy (STM) and frequency modulation atomic force microscopy (FM-AFM) experiments, is reported. The carbon fiber tips were electrochemically etched in a KOH or NaOH solution, using different electronic devices. CF tips with an apex radius ∼10 nm, as deduced from the measured slopes of the Fowler–Nordheim plots (kR < 70 nm for k ∼ 6), were routinely obtained with a homemade electronic device that controls the intensity of the etching current. Then, these conductive CF tips were also characterized by imaging the 6H-SiC(0 0 0 1) surface covered by an epitaxial graphene layer in ultra-high vacuum (UHV). The lattice of the R30° reconstruction was regularly imaged by STM working either in non-oscillating mode or in dynamic mode, which also maps the variations of the force gradient. From these measurements with a constant mean-tunneling-current of 20 pA, it was found that the STM tip suffered variations of the tip/surface force gradient in between 8.25 and 16.50 N/m when it scanned the epitaxial graphene layer on the reconstructed 6H-SiC(0 0 0 1) surface.
URI : http://cybertesis.uni.edu.pe/handle/uni/4145
ISSN : 0008-6223
Correo electrónico : jmoranm@uni.edu.pe
Derechos: info:eu-repo/semantics/embargoedAccess
Aparece en las colecciones: Instituto General de Investigación

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