Enhancement of electrical conductivity in sprayed ZnO thin film through zero-energy process

Conductivity enhancement in spray pyrolysed ZnO thin film was achieved through post-deposition cooling. We present a comparison between the effect of cooling after the deposition of thin films by two different processes namely 'regular cooling' and 'inversion cooling'. X-ray photoelectron spectroscopy studies proved that zinc to oxygen ratio enhanced after the 'inversion' process. It was observed that the process of 'inversion' has caused dramatic improvement in the conductivity of ZnO thin film. The resistivity of the film decreased to 5x10-2 Ω cm with the inversion process. The films exhibited luminescence in two regions:'near band edge emission' (NBE; ∼380 nm) and 'blue-green emission' (∼503 nm). The relationship between blue-green emission and oxygen concentration in the sprayed ZnO thin film was discussed.