Investigation of Al doping concentration effect on the structural and optical properties of the nanostructured CdO thin film

• Nanostructured CdO films with Al dopind were fabricated by ultrasonic spray coating technique.
• Structural property of the nanostructured CdO films was investigated by XRD.
• The optical band gap value of the film increases with the increase in Al doping level.
• The grain size of the films decreases with the Al dopant content via AFM.
• The optical band gap, and grain size of the nanostructured CdO film could be modified by Al doping.

Nanostructured aluminium (Al) doped cadmium oxide (CdO) films with highly electrical conductivity and optical transparency have been deposited for the first time on soda-lime glass substrates preheated at 250 °C by ultrasonic spray coating technique. The aluminium dopant content in the CdO film was changed from 0 to 5 at%. The influencing of Al doping on the structural, morphological, electrical and optical properties of the CdO nanostructured films has been investigated. Atomic force microscopy study showed the grain size of the films is an order of nanometers, and it decreases with increase in Al dopant content. All the films having cubic structure with a lattice parameter 4.69 Å were determined via X ray diffraction analysis. The optical band gap value of the films, obtained by optical absorption, was found to increase with Al doping. Electrical studies exhibited mobility, carrier concentration and resistivity of the film strongly dependent on the doping content. It has been evaluated that optical band gap, and grain size of the nanostructured CdO film could be modified by Al doping.