STRUCTURAL AND ELECTRICAL CHARACTERIZATION OF COBALT OXIDE SEMICONDUCTORS

In this work, it was investigated electrical and structural properties of porous cobalt oxide film that was grown on glass substrate via sol-gel method. The electrical parameters measurement was made using the Van der Pauw technique. Structural and morphological studies have been carried out by means of SEM, and AFM. As-deposited cobalt oxide films showed amorphous nature as confirmed from X-ray diffraction studies. It was shown that annealing influences the grain size of the nanosized cobalt oxide grains. Changes in direct band gap energy and electrical resistivity of as-deposited cobalt oxide films were confirmed after annealing. Spherical grains were uniformly distributed over the substrate surface. In thicker films appears an improvement in crystallinity and grain size which induce higher conductivity. The conductivity of cobalt oxide based films exhibits ρ values between 10-3-103 -1cm-1, depending on the conditions of the annealing.