Metal-insulator transition in Pt-C nanowires grown by focused-ion-beam-induced deposition

Journal Article · Fri May 01 00:00:00 EDT 2009 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.79.174204· OSTI ID:21287008

Fernandez-Pacheco, A; Ibarra, M R ^[1]; De Teresa, J M ^[2]; Cordoba, R ^[1]

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1. Instituto de Nanociencia de Aragon, Universidad de Zaragoza, Zaragoza 50009 (Spain)
2. Instituto de Ciencia de Materiales de Aragon, Universidad de Zaragoza-CSIC, Facultad de Ciencias, , Zaragoza 50009 (Spain)

We present a study of the transport properties of Pt-C nanowires created by focused-ion-beam (FIB)-induced deposition. By means of the measurement of the resistance while the deposit is being performed, we observe a progressive decrease in the nanowire resistivity with thickness, changing from 10{sup 8} {mu}{omega} cm for thickness {approx}20 nm to a lowest saturated value of 700 {mu}{omega} cm for thickness >150 nm. Spectroscopy analysis indicates that this dependence on thickness is caused by a gradient in the metal-carbon ratio as the deposit is grown. We have fabricated nanowires in different ranges of resistivity and studied their conduction mechanism as a function of temperature. A metal-insulator transition as a function of the nanowire thickness is observed. The results will be discussed in terms of the Mott-Anderson theory for noncrystalline materials. An exponential decrease in the conductance with the electric field is found for the most resistive samples, a phenomenon understood by the theory of hopping in lightly doped semiconductors under strong electric fields. This work explains the important discrepancies found in the literature for Pt-C nanostructures grown by FIB and opens the possibility to tune the transport properties of this material by an appropriate selection of the growth parameters.

• OSTI ID: 21287008
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 79, Issue 17; Other Information: DOI: 10.1103/PhysRevB.79.174204; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
CARBON
DEPOSITION
DEPOSITS
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRIC FIELDS
ION BEAMS
NANOSTRUCTURES
PHASE TRANSFORMATIONS
PLATINUM
QUANTUM WIRES
SEMICONDUCTOR MATERIALS
SPECTROSCOPY
TEMPERATURE DEPENDENCE
THICKNESS