Journal of Materials Science

, Volume 24, Issue 5, pp 1819–1826 | Cite as

Electrical properties of carbon-doped KNO3 thin layers

  • F. El-Kabbany
  • S. Taha
  • E. H. El-Khawas


A series of carbon-doped KNO3 thin layers was grown from the melt by a special technique. The changes of the dielectric constant, d.c. resistivity, energy of vacancy formation, pyroelectric current and ferroelectric hysteresis loops with carbon concentration were investigated. The present study aims to clarify the effect of doping carbon as a conducting material on the properties of the dielectric KNO3 thin layers by extensive use of experimental data from isomorphous sets of solid solutions of carbon and KNO3. These systems were studied in the vicinity of the order-disorder phase transition region for various values of carbon concentrationx betweenx=0 andx=0.08. For the carbon doped layers, large changes in the electrical properties were found depending on the doped carbon concentration. The dielectric constant and d.c. resistivity were reduced appreciably, while the pyroelectric current showed improved behaviour in the presence of carbon, as compared with pure KNO3 thin layers. Anomalous ferroelectric hysteresis loops were obtained in carbon-doped layers with a reduction of the ferroelectric loop temperature region by ca. 10° C at carbon concentrationx=0.07. The ferroelectric loops of the carbon-doped layers could be obtained <x = 0.07 with little loop deformation. The results showed that the carbon doping process delayed the phase transition point by 5 to 6° C forx=0.06. Also, the energy of vacancy formation showed its minimum value of 0.45 eV atx=0.03 to 0.04. The marked change in the detailed character of the different electric properties of the doped layers during phase transition in the presence of carbon was interesting.


Phase Transition Dielectric Constant Carbon Concentration KNO3 Vacancy Formation 
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Copyright information

© Chapman and Hall Ltd. 1989

Authors and Affiliations

  • F. El-Kabbany
    • 1
  • S. Taha
    • 1
  • E. H. El-Khawas
    • 1
  1. 1.Physics Department, Faculty of ScienceCairo UniversityCairoEgypt

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