The application of low energy electron microscopy and photoemission electron microscopy to organic thin films
In: Journal of Physics: Condensed Matter, Jg. 20 (2008) ; Nr. 18, S. 184007
ISSN: 0953-8984, 1361-648X
Zeitschriftenaufsatz / Fach: Physik
Fakultät für Physik » Experimentalphysik
Over the last few years, low energy electron microscopy and photoemission electron microscopy have been successfully used to study the growth dynamics of various organic semiconductors. In the present work, the recent advances in the application of surface sensitive electron microscopy techniques to organic thin films are reviewed, and the requirements for successful imaging of organic molecules in low energy electron microscopy and photoemission electron microscopy are discussed. Starting from a discussion of the basic design features of the microscopes, a variety of imaging modes are presented to illustrate the type of information that can be gained from in situ surface sensitive electron microscopy. In photoemission microscopy, the contrast greatly depends on the illumination source that is used for imaging. Using a frequency doubled femtosecond Ti:sapphire laser as a light source for photoemission, even electronic states within the molecules can be directly used for imaging in two-photon photoemission electron microscopy. The article focuses on the two linearly conjugated molecules pentacene (C22H14) and anthracene (C14H10) as model systems.