SOURCE:

Faculty: Physical Sciences
Department: Physics And Industrial Physics

CONTRIBUTORS:

Umeokwonna N. Sunday
Ekwo P.I.
Ekpunobi A. J.

ABSTRACT:

Some magnetic oxide semiconductors; NiCo2O4, MgCo2O4, CdCo2O4 and AgCoO2 were grown by electrodeposition method. Effect of deposition time, deposition voltage and percentage cobalt as dopant on the optical properties were determined. The samples were optically characterized using UV-VIS spectrophotometer in the UV-VIS-NIR regions of electromagnetic spectrum. Results show that NiCo2O4 has band gap that decreased from 3.8eV to 1.0eV as percentage cobalt dopant increased, maximum absorbance of 3.5% in UV region and maximum transmittance of 99.4% in the visible region. MgCo2O4 has bandgap that decreased from 4.4eV to 2.6eV as percentage cobalt dopant increased, maximum absorbance of 8% in UV region and maximum transmittance of approximately 100% in NIR. CdCo2O4 has bandgap that decreased from 2.2eV to 1.5eV as percentage cobalt dopant increased, maximum absorbance of 15% in UV region and maximum transmittance of 98.7% in NIR. AgCoO2 has bandgap that increased from 2.6eV to 4.1eV as percentage cobalt dopant increased, maximum absorbance of 6% for 3% Co doped in UV-VIS-NIR regions and maximum transmittance of 98.5% for 23% Co doped in NIR region. Magnetic property was characterized with Microsense VSM system. Thickness of the films was characterized with profilometer while compositional property was done by X-ray flourescence spectrometer. Results of the study show that the optical properties of the films viz; absorbance, reflectance, refractive index, extinction coefficient, complex dielectric constant and optical conductivities of NiCo2O4, MgCo2O4, CdCo2O4 increased as deposition time, deposition voltage and percentage cobalt dopant increased, but in case of AgCoO2 they increased as deposition voltage and deposition time increased but decreased as percentage cobalt dopant increased. However the transmittance of the films NiCo2O4, MgCo2O4 and CdCo2O4 decreased as deposition voltage, deposition time and percentage cobalt dopant increased but in case of AgCoO2 , it decreased as deposition voltage and deposition time increased but increased as percentage cobalt dopant increased. Thickness of NiCo2O4, MgCo2O4 and CdCo2O4 films increased as percentage cobalt dopant, deposition voltage and deposition time increased but in case of AgCoO2 it increased as deposition voltage and deposition time increased but decreased as percentage cobalt dopant increased.