INFLUENCE OF THE GROWTH TEMPERATURE ON THE PROPERTIES OF Mn-DOPED SnO₂ THIN FILMS GROWN BY PULSED LASER DEPOSITION

Mn-Doped SnO₂ thin films were grown on sapphire (012) substrates by pulsed laser deposition. The influence of substrate temperature on the film properties was investigated. X-ray diffraction patterns show that the thin films grown at lower substrate temperatures were amorphous, while those grown at higher temperatures had only a single (101) orientation. Atomic force microscopy results indicate that the films grown at low temperature were extremely flat and they became rougher as substrate temperature (T_s) increased. Optical transmission spectra reveal that the absorption edge shifts towards the blue side and becomes steeper at increasing T_s. High-resolution transmission electron microscopy analysis clearly indicates that the samples have a well-arranged tetragonal structure without any detectable secondary phase. Inhomogeneous incorporation of Mn atoms into the SnO₂ lattice was also observed.