Effect of surface passivation on electrical properties of Pd-F: SnO 2 thin films prepared by spray pyrolysis technique

Abstract

Pd-F:SnO 2 thin films have been prepared by spray pyrolysis technique. Optimization has been done by doping SnO 2 with palladium at varying levels of concentration and then recording sheet resistance. The sheet resistivity has been observed to decrease gradually as at% Pd concentration is increased; an optimum sheet resistivity value of 2.71 × 10 -2 Ω cm has been recorded. The decrease in sheet resistivity has been attributed to presence of Pd ions which contribute in increment of charge carrier density. Using the optimum value of at% Pd doping, the same procedure has been repeated to study the effect of fluorine on Pd:SnO 2 ; an optimum value of 1.64 × 10 -4 Ω cm sheet resistivity has been recorded. This decrease has been attributed to substitution of O- with those of fluorine hence improving charge carrier density. The effect of passivation has been studied by comparing as prepared, annealed and passivated Pd-F:SnO 2 thin films. Annealing has been observed to decrease the sheet resistivity to 1.21 × 10 -4 O cm, while passivation has the effect of increasing the sheet resistivity to 1.53 × 10 -4 O cm which is attributed to effects resulting from annealing the samples in nitrogen gas atmosphere.