Detection of the Nanostructures in ZnO Thin Films by Using Optical Methods
The ZnO films deposited by reactive magnetron sputtering are investigated. SEM provides information on the composition of the films and enables us to observe the nanostructures. AFM provides information on the roughness and the texture of the surfaces. Fourier transform, photoluminescence and Raman scattering are used for confirmation of appropriate results. The spectral dependences of ellipsometric parameters Δ and Ψ are determined by ellipsometry and the effective values of optical constants n and k are calculated. As it can be indicated, the nanostructures in ZnO film are formed when reducing base pressure down to 2.5•10-7 mbar and elevating the temperature of the substrate up to 5500C. The amorphous structure is formed in most of other films (crystalline structure is formed at rather special conditions). Films containing considerable portions of impurities (generally carbon impurities) are formed at reduced base pressure. The values of optical constants of some of the films fit the appropriate Dumont and Jellison tabulations satisfactorily.
M. Rakov et al., "Detection of the Nanostructures in ZnO Thin Films by Using Optical Methods", Advanced Materials Research, Vol. 222, pp. 185-188, 2011