First investigation of structural and optoelectronic properties of F and Ni co-doped SnO2 sprayed thin films

Abstract Transparent conducting Nickel-fluorine co-doped tin oxide (SnO2: (Ni, F)) thin films were synthesized chemically by spray pyrolysis technique (CSP) using various Ni concentrations onto hot glass substrates. The [Ni2+]/[Sn4+] atomic concentration ratio (y) in the spray solution was varying from 0 to 3 at. % by a step of 1 at. %. The y variation effect on the structural, optical and electrical properties was studied. It was found from the X-ray diffraction analysis that the films were polycrystalline with tetragonal structure corresponding to pure SnO2 phase having the (200) as preferred growth direction. The optical band gap energy increased from 3.71 to 3.88 eV with increasing the nickel doping concentration in the spray solution. Photoluminescence behaviour of Ni-F co-doped SnO2 thin films was also studied. In addition, electrical resistivity (ρ), volume carrier concentration (Nv), and Hall mobility (μ) were determined from Hall Effect measurements and it was found that all the elaborated thin films had n-type conductivity. The lowest resistivity of 3.16 × 10-5 Ω.cm, and highest Hall mobility of 10.07 × 105  cm2.V-1.s-1 were obtained at a Ni concentration of 3 at. %.