Synthesis, Morphology, Optical and Electrical Properties of Cu_1−xFe_xO Nanopowder

Abstract

The pure and Fe-doped CuO nanoparticles of the series Cu(1−x) Fe(x)O (x = 0, 0.027, 0.055, 0.097 and 0.125) were synthesized by a simple low temperature sol–gel method. Synthesized samples were characterized by a series of techniques including Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray electron spectroscopy (EDX), Diffuse Reflectance Spectroscopy (DRS), Fourier Transform Infrared Spectroscopy (FTIR), Hall Effect Set-up and Current–Voltage (I–V) characteristics. FESEM analysis shows formation of disc type structure increasing in grain size with Fe concentration in CuO. EDX confirmed the incorporation of iron in CuO. FTIR results of pure and Fe doped CuO samples have confirmed the formation of monoclinic CuO. The optical band gap estimated using Diffuse Reflectance Spectroscopy (DRS) shows the increment in the band gap values with Fe substitution. The Hall measurements show predominantly p-type conduction in all the samples and carrier densities decrease with increased Fe substitution. I–V characteristics of pure and Fe doped CuO nanoparticles show rectification behaviour of Schottky diodes.

Cu 1– x Fe x O: hopping transport and ferromagnetism

“…Fe 3+ ion having a different ionic radius is a most likely source of internal strain. It not only creates localized defects but also reduces single crystal domain size within the same Cu 1−x Fe x O grain as already reported in SEM studies [12]. E a and σ 0 decreases with increasing substitution (figure 4a, inset).…”

“…E a and σ 0 decreases with increasing substitution (figure 4a, inset). The decreasing trend of σ dc of these samples was also directly calculated from I-V characteristics and was reported previously [12].…”

“…However, due to significantly p-type CuO host these excess electrons cannot improve the conductivity. It was reported from Hall measurements that p-type carrier concentration decreased [12], reducing the net conductivity of the material with increasing substitution. Reduction in oxygen vacancies with increasing Fe content was found from EXAFS analysis [13] due to extra charge of Fe 3+ than Cu 2+ ions.…”

“…We have synthesized nanocrystalline Cu 1 –x Fe x O ( x  = 0, 0.027, 0.055, 0.097 and 0.125) powders, with extreme care on homogeneity, by standard Pechini sol–gel process [12]. A sol–gel prepared sample allows proper mixing of the constituent ions.…”

Role of compensating Li/Fe incorporation in Cu0.945Fe0.055−xLixO: structural, vibrational and magnetic properties

“…Nanocrystalline Cu 0.945 Fe 0.055Àx Li x O (0 # x # 0.055) powders were synthesized by sol-gel method as previously reported. 30 Copper(II) oxide (99.7%, Alfa Aesar, metal basis) iron(III) nitrate nonahydrate (98%, Alfa Aesar), lithium nitrate, anhydrous (99.999% Alfa Aesar, metal basis), citric acid anhydrous (assay 99% Merck) and nitric acid (assay 69% Merck) were used as precursors. Required amount of precursors were dissolved in DI water separately and mixed together.…”