Morphology and ellipsometry study of pentacene films grown on native SiO2 and glass substrates

We have studied the morphology and optical properties of pentacene films in the thickness range of 300–600 nm using atomic force microscopy and spectroscopic ellipsometry. The films were grown on native SiO2 and glass substrates at room temperature and 80 °C. Surface images showed that the films were formed by the grain growth. The grains were bigger when the films were grown at 80 °C, but this was accompanied with the diminished crystalline ordering. Even though the thickness was the same, the ellipsometry spectra were different for the samples grown under different condition. When the room temperature sample was annealed at 150 °C for 1 h the ellipsometry spectrum did not change indicating that the pentacene film is thermally stable.