We have examined the dynamics of adsorption of diindenoperylene (DIP) on SiO2 and SiO2 modified with an interfacial organic layer using in situ real time synchrotron x-ray scattering, focusing on the effects of coverage. On both surfaces we observe a substantial increase in the probability of adsorption with increasing coverage, which is most dramatic at the highest incident kinetic energies. On the initially uncovered surfaces, we observe a smooth decrease in the probability of adsorption with increasing incident kinetic energy, indicative of trapping-mediated adsorption. Once both surfaces are covered by DIP, the effects of incident kinetic energy are greatly reduced, and trapping is very efficient over the range of kinetic energies examined. Possible reasons for efficient trapping at high coverage and at high incident kinetic energy include more efficient momentum transfer due to mass matching, and possibly direct molecular insertion. Comparison to results on another small-molecule, pentacene, suggests that this behavior should be common to hyperthermal growth of a variety of other small-molecule thin films.
|Original language||English (US)|
|Journal||Journal of Chemical Physics|
|State||Published - 2009|
Bibliographical noteFunding Information:
This work was supported by the Cornell Center for Materials Research, a National Science Foundation MRSEC (Grant No. NSF-DMR-0520404), and was performed in part at the Cornell High Energy Synchrotron Source, also supported by the NSF and NIH-NIGMS (Grant No. NSF-DMR-0225180). J.R.E. would like to also acknowledge supplementary support via NSF-ECS-0210693 and NSF-CTS-0529042. S.H. and A.A. would like to acknowledge the Korea Research Foundation (Grant No. KRF-2006-352-D00108) and the Natural Sciences and Engineering Council of Canada, respectively, for post-doctoral fellowships.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry