An ultrafast atomic layer deposition technique is presented, based on the spatial separation of the half-reactions, by which alumina layers can be deposited with deposition rates of more than 1 nm/s. The deposition rate is limited by the water half-reaction, for which a kinetic model has been developed. The alumina layers showed excellent passivation of silicon wafers for solar cell applications. Based on this concept, a high-throughput ALD deposition tool is being developed targeting throughput numbers of up to 3000 wafers/h.

In this paper, we report the structural and electronic properties of pentacene thin films grown on a polycrystalline Co film using atomic force microscopy and ultraviolet photoemission spectroscopy ͑UPS͒, respectively. Investigation of this type of interface is of importance for the engineering of hybrid organometallic spintronic devices for which the use of spin polarized electrodes is a prerequisite. Uniform single crystalline areas of pentacene as large as several micrometers, with molecules arranging almost perpendicular to the substrate, were obtained. For the electronic properties at this interface, we have found an energy barrier for the hole injection of about 1 eV, in spite of the fact that the ionization potential of pentacene reported previously equals the work function of Co. A shift of the vacuum level of the same magnitude has also been observed. A comparison of the UPS spectra of the pentacene films with the gas phase spectrum directly indicates that hybridization effects are present at this interface. © 2006 American Institute of Physics. ͓DOI: 10.1063/1.2363707͔ INTRODUCTIONMolecular organic semiconductors have become a very active area of research during the past decade. The structural flexibility due to weak intermolecular bonds and the endless possibilities for chemical synthesis of new molecules give molecular systems a unique advantage over inorganic semiconductors for relatively simple fabrication of ͑opto-͒ electronic devices such as light emitting diodes for flexible or even transparent displays, transistors, solar cells, sensors, and solid state lasers. Applications into electronic devices in which the spin degree of freedom of the electron is exploited ͑spintronics͒ have recently started to be considered, motivated by the notion that organic semiconductors are materials with large spin relaxation times. [1][2][3][4][5] Spin valves with a significant magnetoresistance have been produced with Alq 3 thin films sandwiched between two ferromagnetic electrodes. 4,5 In response to the technological success of the organic semiconductors, fundamental research, with the goal of understanding the surface and interface properties of these systems, has followed. Such studies have proven to be valuable for device engineering, as well as from the fundamental viewpoint, electronic properties of interfaces between organic semiconductors and metals being still puzzling for scientists. While the electronic and structural properties of large organic molecules on noble metals and semiconducting or semimetallic substrates have been extensively studied, only a limited number of studies on more reactive substrates, such as the ferromagnetic transition metals, have been reported. 6 Such investigations are of crucial relevance to understand and control efficient spin injection from ferromagnetic electrodes into organic thin films.In the ferromagnetic transition metals, both the magnetic behavior and the reactivity originate from the high density of the d states near the Fermi level. For the structural propertie...

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