Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 4: Nanostructures I
O 4.7: Vortrag
Montag, 27. März 2006, 12:45–13:00, PHY C213
Innovative Quantum Devices based on C60 -Nanodots — •Oliver S. Senftleben, Tanja Stimpel-Lindner, Hermann Baumgärtner, and Ignaz Eisele — Institut für Physik EIT9.1, Universität der Bundeswehr München, 85577 Neubiberg
Thermal evaporation of pure C60 molecules is very suitable for the fabrication of new quantum devices. Observation of quantum effects like Coulomb-Blockade or coherent tunnelling can only be observed at room temperature if capacities are in the range of sub-atto-farad regime to exceed thermal noise. Hence the feasibility of extremely thin oxides as well as the behaviour of C60 under high temperatures (400-850∘C) and oxygen atmosphere is of very high importance. Experiments have been performed in a UHV chamber to avoid any surface contamination during process and to allow in-situ process control with AES, LEED, STM and STS. Thermal oxidation of Si has been studied under several pressures (10−5 to 10−3 mbar) and temperatures (RT to 850∘C). The experiments have shown that oxide-growth is possible up to a thickness of 2 nm. C60 films of different coverage have then been studied under these environmental conditions. C60 on pure Si shows no chemical reaction with oxygen up to 800∘C und a pressure of 10−4 mbar. This has been verified by STM and AES. The behaviour of C60 on SiO2 during annealing has been observed under UHV conditions and oxygen pressures up to 10−4 mbar. First experiments indicate a weaker binding of C60 to the SiO2 than to the Si(100)-2x1 surface and therefore a higher desorption rate at elevated temperatures. Finally first STS results of C60 on UHV grown oxides are presented.