Photocatalytic response of Fe, Co, Ni doped ZnO based diluted magnetic semiconductors for spintronics applications

摘要

Novel attempts were made to prepare diluted magnetic semiconductors separately with 10 at.% each of Fe, Co and Ni doped ZnO by sol-gel method. The XRD analysis of the films detect wurtzite ZnO as the pure phase present in the synthesized films. The average particle size of 10 at.% Fe, Co, Ni doped and pristine ZnO derived films are found as 10.01 nm, 12.03 nm, 15.36 nm and 16.16 nm respectively. The absorbance spectra of the oxides reveal intrinsic band gap of ZnO, Fe2O3, CoO and NiO are 3.29 eV, 2.53 eV, 2.42 eV and 3.64 eV respectively. The near band edge absorbance of pure ZnO was recorded as about 377 nm (similar to 3.29 eV) which shifts to lower wavelength with reduction in particle size in Ni, Co and Fe doped ZnO sample as the effect of quantum confinement. The PL spectra of the developed films reveal multiple peaks between 450 nm and 500 nm, on excitation wavelength at 370 nm, as the evidence of photochemical properties of the samples. Vibrating sample magnetometer analysis reveals 10 at.% Fe doped ZnO posses minimum value of squareness 0.118 and coersivity 177.738 Oe which prove it to be the best magnetic material among all four samples prepared. Raman spectra show evidence of phonon confinement for 10 at.% Fe doped ZnO sample by broadening of E-g, T-2g and A(1g) peaks, which is not so prominent for other samples. In addition, the photochemical degradation reaction is maximum for 10 at.% Fe doped ZnO sample which proves to be most suitable material for optoelectronic devices.