Electrically conductive properties of tungsten-containing diamond-like carbon films

Takanori Takeno, Hiroyuki Miki, Toshiyuki Takagi, Hideya Onodera

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

Tungsten-containing diamond-like carbon films with different metal concentrations were investigated. The films of several hundred nanometers in thickness were deposited on the silicon wafer using RF-PECVD (radio frequency plasma enhanced chemical vapor deposition) method. During deposition, metal component was co-sputtered using DC magnetron of tungsten target. The six samples with the concentration of 3.8, 6.1, 8.0, 16.3, 24.3 and 41.4 at.% of tungsten were made. The structural analyses were performed by TEM (transmission electron microscope) and Raman spectroscopy. These results indicated that tungsten clusters were well dispersed in amorphous carbon host matrix in the case of tungsten concentration from 3.8 to 24.2 at.%. However, no such a structure can be observed in the sample with 41.4 at.%. The AC electrical resistance was measured in the temperature range of 2-300 K using four-probe method in vacuum condition. The observed temperature dependence of electrical conductivity can be expressed by σ = σ0 exp ⌊ - 2 (C0 / k T)1 / 2 ⌋ and tungsten concentration from 3.8 at.% to 24.2 at.%. In addition, the sample with 41.4 at.% showed the resistive superconducting transition at Tc of around ∼ 5.5 K.

Original languageEnglish
Pages (from-to)1902-1905
Number of pages4
JournalDiamond and Related Materials
Volume15
Issue number11-12 SPEC. ISS.
DOIs
Publication statusPublished - 2006 Nov

Keywords

  • Diamond-like carbon
  • Effective barrier height
  • Electrical conduction
  • Tungsten

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Chemistry(all)
  • Mechanical Engineering
  • Materials Chemistry
  • Electrical and Electronic Engineering

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