Improved transparent conductive properties of highly c-axis oriented ZnO thin films upon (Ga, Mg) co-doping

The paper reports the growth and characterization of highly c-axis oriented ZnO thin films and their physical properties upon (Ga, Mg) co-doping. The films were produced on glass substrates by sol-gel spin-coating technique. X-ray diffraction (XRD) patterns of all the films reveal the presence of a hexagonal wurtzite crystal structure of ZnO with a c-axis preferred orientation and crystallite sizes in the range of 28-50 nm. Surface morphological studies reveal the granular morphology of the films. The optical transparency in the visible region increases upon doping and co-doping with a maximum (>95%) for the (1 at% Ga +3 at % Mg) co-doped ZnO thin film (assigned with code name 1G3MZO). The band gap is blue-shifted upon co-doping and found to be a maximum of 3.32 eV for the 1G3MZO film. The electrical conductivity improves upon co-doping, and an optimum value of 70.3 (O-cm)(- 1) is obtained in the 1G3MZO film. It has been concluded that the 1G3MZO film has improved transparent conductive properties and, therefore, finds application in optoelectronic devices.