Structural and electrical properties of carbon-ion-implanted ultrananocrystalline diamond films

Hui Xu, Jian Jun Liu, Hai Tao Ye, D. J. Coathup, A. V. Khomich, Xiao Jun Hu*

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

We investigate the structural and electrical properties of carbon-ion-implanted ultrananocrystalline diamond (UNCD) films. Impedance spectroscopy measurements show that the impedance of diamond grains is relatively stable, while that of grain boundaries (GBs) (Rb) significantly increases after the C+ implantation, and decreases with the increase in the annealing temperature (Ta) from 650 °Cto 1000 °C. This implies that the C+ implantation has a more significant impact on the conductivity of GBs. Conductive atomic force microscopy demonstrates that the number of conductive sites increases in GB regions at Ta above 900 °C, owing to the formation of a nanographitic phase confirmed by high-resolution transmission electronic microscopy. Visible-light Raman spectra show that resistive trans-polyacetylene oligomers desorb from GBs at Ta above 900 °C, which leads to lower Rb of samples annealed at 900 and 1000 °C. With the increase in Ta to 1000 °C, diamond grains become smaller with longer GBs modified by a more ordered nanographitic phase, supplying more conductive sites and leading to a lower Rb

Original languageEnglish
Article number096104
JournalChinese Physics B
Volume27
Issue number9
DOIs
Publication statusPublished - 1 Sep 2018

Keywords

  • Annealing
  • C-ion implantation
  • Electrical properties
  • Ultrananocrystalline diamond

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