Characteristics of Fe- and Mg-doped CuCrO2 nanocrystals prepared by hydrothermal synthesis
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Date
2016
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Publisher
SPRINGER
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info:eu-repo/semantics/closedAccess
Abstract
A series of Cu(Cr1-xFex)O-2 and Cu(Cr1-yMgy)O-2 (0.0 <= x,y <= 0.05) nanocrystalline samples with high surface area were prepared using hydrothermal synthesis. The effect of Fe3+ substitution for Cr3+ on the structural, morphological, optical and electrical characteristics of CuCrO2 nanoparticles was investigated in comparison with Mg-doped samples. X-ray diffraction study showed that the solubility limit was around 3 at% for both dopants and beyond this concentration the formation of spinel phases was observed. The incorporation of the tri- and divalent dopants induced a slight expansion in a- and c-parameters. Transmission electron microscopy examination indicated that the average crystallite size (12 nm for undoped) decreased with increasing doping amount of up to x = 0.03 (8.5 nm) and y = 0.05 (7 nm). Moreover, the introduction of Fe and Mg led to an increase in the size distribution of the crystallites. All samples exhibited transmittance above 80 % at 700 nm wavelength and transmittance was enhanced for all doping concentrations except for x = 0.05. A similar trend was also observed for the direct band gaps, where only 5 at% Fe doping induced a red-shift of Eg. The direct band gaps were estimated to be 3.09 eV for x = 0.03 and 3.07 eV for y = 0.03. At room temperature, the minimum achieved electrical resistivity was measured to be 6.4 and 0.068 k Omega cm for the samples with x, y = 0.03, respectively. These values are lower by a factor of similar to 2 and 166 than that of the undoped CuCrO2 sample (11.8 k Omega cm). All samples behaved like semiconductors, and the thermally activated energy for Cu(Cr0.97Mg0.03)O-2 and Cu(Cr0.97Fe0.03)O-2 pellets were found to be 45.40 and 92.5 meV, respectively.
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Journal or Series
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
WoS Q Value
Q2
Scopus Q Value
Q2
Volume
27
Issue
3
