ISSN:
0142-2421
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
We have succeeded in preparing very thin (nanometre order) alternating layers that can be called ‘organic superlattices’ by using a special combination of materials, substrates and deposition conditions with good verification by various characterization techniques.Specially surface-treated single-crystal silicon substrates with hydrogen-terminated dangling bonds on the surface were used to induce van der Waals heteroepitaxial growth. Choice of materials with the appropriate molecular shapes and aggregation force is also important for preparing flat molecular films. Tetraphenylporphyrins (H2TPP and ZnTPP) and phthalocyanines were used for this purpose. A molecular beam epitaxy chamber with specially designed cells was used with the cooled substrates.Direct proof of the alternating composition was given by transmission electron microscopy observation, avoiding decomposition by the electron beam, and also by SIMS depth profiling under special conditions to ensure good depth resolution. X-ray diffraction in the small-angle region gives the periodicity of the alternating layers, as well as their crystal quality. Atomic force microscopy confirms the atomic flatness and also gives the molecular orientation in the films. Fourier transform infrared spectroscopy examines the chemical stability of the compounds during deposition and also gives the axial orientation of the molecules in the films.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/sia.740210606
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