Spray pyrolysis growth of ZnSnO thin films: structural and morphological analysis [Articol]

Abstract

Zinc tin oxide (ZnSnO) thin films were synthesized at different deposition times via spray pyrolysis to investigate the effect of film thickness on structural and morphological properties. SEM surface and cross-sectional measurements showed that with increasing deposition time the film thickness increased from 80 nm (3 min) to 320 nm (10 min). At the same time, the surface morphology evolved from uniform, compact layers with smaller crystallites to denser structures with larger grains. This transition was attributed to the competition between nucleation and growth during film formation. XRD analysis confirmed the coexistence of Zn₂SnO₄ and SnO₂ phases in all samples. With increasing thickness, the relative intensity of Zn₂SnO₄ peaks increased while SnO₂ peaks decreased, indicating preferential stabilization of Zn₂SnO₄ in thicker films. In particular, the (110) peak of SnO₂ diminished, whereas the (220) peak of Zn₂SnO₄ became more pronounced, evidencing progressive phase transformation. These results indicate a clear correlation between deposition time, film thickness, crystallite size, and phase composition, while the optical transparency decreases from 84% to 72% as the thickness increases from 80 nm to 320 nm.