Effects of Boron Doping on Structural, Optical and Electrical Properties of Cadmium Oxide Thin Films Prepared by Sol-Gel Spin Coating Method

Undoped and boron (B) doped cadmium oxide (CdO) thin films were obtained using cadmium acetate dehydrate and boric acid as precursor solutions by sol-gel spin coating method. The films were annealed at 500 oC and structural, electrical, optical and surface properties have been investigated. The recorded X- ray diffraction patterns indicated that all the films had preferential orientation along (111) plane and fit well with the cubic crystal structure. The minimum resistivity of 1.71×10-3 Ω cm was obtained for the film doped with 2.5 wt% boron. Scanning electron microscopy (SEM) images indicates that the boron doping was strongly influenced on surface morphology. An EDX spectrum shows that Cd and O elements are present in the solid films. Optical spectra showed that the average transmittance of doped films over 80 % in the visible region and the obtained optical band gap is higher (2.56 – 2.59eV) than the undoped (2.23eV) cadmium oxide thin films.