Studies on micro-structural and electrical properties of spray-deposited fluorine-doped tin oxide thin films from low-cost precursor

Thin films of fluorine-doped tin oxide $(SnO_2:F)$ on glass were prepared by spray pyrolysis technique using stannous chloride $(SnCl_2)$ and ammonium fluoride $(NH_4F)$ as precursors. The as-prepared films were characterized for their structural and electrical properties and are discussed in detail in this article. The surface morphology studies revealed that the films are grainy and the roughness of undoped films has been reduced on fluorine doping. X-ray diffraction (XRD) studies revealed that the films are polycrystalline. It further revealed that the undoped films grow along the preferred orientation of (211), whereas all the doped films grow along (200). The minimum sheet resistance $1.75 \Omega/sq$ achieved in the present study for the films doped with 15 wt.% F is the lowest among the reported values for these materials prepared using $SnCl_2$ precursor. The electrical transport phenomenon has been analyzed in order to find out the possible scattering mechanism that limiting the mobility of charge carriers