Structural, morphological, optical and electrical properties of Ni-doped SnO2 thin films by pneumatic spray pyrolysis method

In this study, we used a pneumatic spray pyrolysis technique at 450 degrees C to deposit Sn1-xNixO2 thin films (0.0 <= x <= 0.10) on glass substrates. The influence of doping content on the films structural, morphological, optical and electrical properties was investigated. Structural characterization by X-ray diffraction indicated that the rutile phase of SnO2 is present in all thin films, and crystallite sizes are estimated to be in the range of 27-47 nm. Furthermore, structural and microstructural analyses revealed that at x = 0.05, there is a solubility limit for (Ni/Sn) in the SnO2 matrix. The optical bandgap energy increases from 3.83 to 4.01 eV as the dopant content increases according to the Burstein-Moss effect. Resistivity is affected by doping and the thickness of thin films. The figure-of-merit calculated for all samples showed significant differences in the Ni-SnO2 thin films. There was a difference between the doped thin films depending on the thickness. The lowest resistivity of 1.32 x 10(-2) Omega cm and the maximum conductivity of 75 Omega(-1) cm(-1) was found at a Ni content of 2%. Seebeck coefficient of all the thin films developed had n-type conductivity, and the values of 76, 71, 133 and 69 mu V/K for Ni-doped SnO2 thin films at 0, 2, 5 and 10 at.%, respectively, were found to improve the thermoelectric properties of SnO2 by Ni doping.