J Mater Sci Technol ›› 2011, Vol. 27 ›› Issue (10): 944-950.

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Effect of Doping and High-Temperature Annealing on the Structural and Electrical Properties of Zn1-XNiXO(0≤X≤0.15) Powders

Hakan Colak, Orhan Turkoglu   

  1. Department of Chemistry, Faculty of Science, University of Erciyes, Kayseri 38039, Turkey
  • Received:2010-07-09 Revised:2010-10-27 Online:2011-10-31 Published:2011-10-24
  • Contact: Hakan ?OLAK

Abstract: This paper reported the synthesis, crystal structure and electrical conductivity properties of Ni-doped ZnO powders (i.e. Zn1-XNiXObinary system, X=0, 0.0025, 0.005, 0.0075 and in the range 0.01≤X≤0.15). I-phase samples, which were indexed as single phase with a hexagonal (wurtzite) structure in the Zn1-XNiXObinary system, were determined by X-ray diffraction (XRD). The widest range of the I-phase was determined as 0≤X≤0.03 at 1200°C; above this range the mixed phase was observed. The impurity phase was determined as NiO when compared with standard XRD data, using the PDF program. We focused on single I-phase ZnO samples which were synthesized at 1200°C because of the widest range of solubility limit at this temperature. It was observed that the lattice parameters a and c of the I-phase decreased with Ni doping concentration. The morphology of the I-phase samples was analyzed with a scanning electron microscope. The electrical conductivity of the pure ZnO and single I-phase samples were studied by using the four-probe dc method at temperatures between 100 and 950°C in air atmosphere. The electrical conductivity values of pure ZnO and 3 mol% Ni-doped ZnO samples at 100°C were 2×10-6 and 4.8×10-6Ω-1?cm-1, and at 950°C they were 1.8 and 3.6Ω-1?cm-1, respectively. In other words, electrical conductivity increased with Ni doping concentration.

Key words: II-VI semiconductors, Zinc oxide and doped zinc oxide, Four point probe method