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Controlled Molecular Alignment in Phthalocyanine Thin Films on Stepped Sapphire Surfaces
Author(s) -
Ossó J.O.,
Schreiber F.,
Kruppa V.,
Dosch H.,
Garriga M.,
Alonso M.I.,
Cerdeira F.
Publication year - 2002
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/1616-3028(20020618)12:6/7<455::aid-adfm455>3.0.co;2-i
Subject(s) - sapphire , materials science , wafer , thin film , silicon , epitaxy , azimuth , raman scattering , raman spectroscopy , optics , scattering , plane (geometry) , crystallography , optoelectronics , molecular physics , nanotechnology , laser , geometry , chemistry , physics , mathematics , layer (electronics)
We report a detailed study of the growth and structure of thin films of copper hexadecafluorophthalocyanine (F 16 CuPc) on sapphire. These films show very good out‐of‐plane order and have X‐ray rocking widths of around 0.02°. If prepared under suitable conditions on A ‐plane sapphire substrates, the molecules align without significant azimuthal dispersion. Growth on MgO (001) and oxidized silicon wafers resulted in a comparable out‐of‐plane structure, but showed no azimuthal order. We find that the azimuthal alignment on sapphire is induced by the step edges along the c ‐axis of the sapphire, which serve as templates for the growth. For growth at different substrate temperatures, we find a monotonic change of the molecular out‐of‐plane tilt angle, as obtained from Raman scattering, which is accompanied by a change of the out‐of‐plane lattice parameter.