Enhancement of the Hackee's quality factor of sol–gel spin coated ZnO thin films by MO doping

Undoped and molybdenum doped zinc oxide (MZO) thin films were deposited onto glass substrates by sol–gel spin coating method. The Mo doping level was varied from 1 to 4 at% in steps of 1 at%. The XRD analysis showed that all the films are polycrystalline with hexagonal wurtzite structure and preferentially oriented along the (002) plane. The optical studies showed that all the films are highly transparent in the visible region (~85%). The film with 2 at% Mo doping exhibits the best Hackee's quality factor (9.0×10−2 (Ω/ϒ)−1). The optical band gap energy is found to increase from 3.23 eV to 3.39 eV with the increase in Mo doping level. Electrical resistivity of the film is found to be minimum (5.52×10−3 Ω cm) when the Mo doping level is 2 at%. The surface morphological study clearly shows that the molybdenum doping induces well defined nano fibers network structure on the surface of the films.