Physical properties of homogeneous TiO@d2 films prepared by high power impulse magnetron sputtering as a function of crystallographic phase and nanostructure

• Published in: Journal of physics. D, Applied physics Applied physics, 2009-05, Vol.42 (10)
• Main Authors: Stranak, V, Cada, M, Quaas, M, Block, S, Bogdanowicz, R, Kment, S, Wulff, H, Hubicka, Z, Helm, C A, Tichy, M, Hippler, R
• Format: Article
• Language: English
• ISSN: 0022-3727
• DOI: 10.1088/0022-3727/42/10/105204

Optical, photo-electrochemical, crystallographic and morphological properties of TiO@d2 thin films prepared by high power impulse magnetron sputtering at low substrate temperatures ( < 65 'C) without post-deposition thermal annealing are studied. The film composition--anatase, rutile or amorphous TiO@d2--is adjusted by the pressure (@ip 6 0.75-15 Pa) in the deposition chamber. The different crystallographic phases were determined with grazing incidence x-ray diffractometry. The surface morphology and size of TiO@d2 grains/clusters were imaged with atomic force microscopy. Basic plasma parameters were determined by means of the time-resolved Langmuir probe technique. The power density influx on the substrate was estimated from calorimetric probe measurement. The data from calorimetric probe measurements and time-resolved Langmuir probe served as input parameters for the calculation of influx contributions of particular species. The band-gap energy @iE@dg depends on the film composition and crystallographic phase. Optical parameters (refractive index @in + i@ik, transmittance @iT, reflectance @iR and absorbance A) are measured as functions of photon energy in the UV-Vis range by spectroscopic ellipsometry. For the rutile and anatase films agreement with the respective bulk phase is found. Incident photon-current conversion efficiency determined by photo-electrochemical measurements reached the highest values (0.312) for the anatase film.