EFFECT OF ANNEALING TEMPERATURE ON THE SURFACE MORPHOLOGY AND ELECTRICAL PROPERTIES OF SnO₂ THIN FILMS

Abstract

This paper presents a structured analysis of the effect of annealing temperature on the surface morphology and electrical behavior of SnO₂ thin films on the basis of scanning electron microscopy observations and semiconductor transport considerations. The results show that, as the annealing temperature increases, the film surface evolves from a relatively porous and weakly crystallized nanostructure toward a dense polycrystalline morphology with larger and more clearly faceted grains. Such evolution is associated with thermally activated atomic diffusion, progressive grain coalescence, and a reduction in the Gibbs free energy of the system. At lower temperatures, the limited mobility of adatoms preserves a high density of grain boundaries and intergranular voids, which enhances potential barriers and suppresses charge transport. At higher temperatures, grain growth and densification reduce the boundary fraction, weaken carrier scattering, and create more continuous conductive pathways. The analysis confirms that annealing temperature is a decisive technological parameter for tailoring the structural quality and functional performance of SnO₂ thin films for semiconductor and optoelectronic applications.