Growth of DIP on Sapphire

We briefly note that annealing to 430 K of thin DIP films (few nm thick) deposited at room temperature leads to an average tilt angle of about 54° as determined by NEXAFS. Since this is the so-called magic angle this result most likely means that the crystallites formed by annealing have random orientation. Thus annealing not always leads to optimum results, at least not in terms of molecular orientation. 

2 pm X 2 pm) of a nominally 2 nm thick DIP fdm deposited on a sapphire surface at a substrate temperature of 330 K. The profiles were extracted along the lines indicated by arrows in the AFM picture. 

Also in the photoemission case the signature of the multilayer spectrum is essentially conserved at the interface, but in this case minor changes occur. The peak at 286.2 eV in the multilayer spectram, which is due to a shake up excitation, is almost completely quenched for the monolayer data. Moreover, the symmetric line shape of the multilayer C Is line is slightly changed in the monolayer it becomes more asymmetric with additional spectral weight on the low energy side. At the same time the line width is slightly reduced from 0.7 eV to about 0.6 eV. While the latter observation could be explained by a 

The spectrum shows a strong increase of the An signal while the C Is line is 

In the present case after a rough test no major deviations from the ideal DlP/Au model system could be detected but further, more detailed studies using high-resolution electron spectroscopies with synchrotron radiation and additional morphological techniques such as AFM may reveal subtle differences. These will be performed after optimisation of the lift-off technique which is presently under way and will be applied completely under UHV conditions, thus allowing the minimisation of spurious influences. Then further investigations on buried interfaces combining XPS, UPS, IPES, NEXAFS, and AFM will be performed on the present and several other systems which are a matter of present research. 

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