Preparation of high-quality organic films by deposition and codeposition from supersonic seeded beams

Recent results obtained in the growth of organic materials by supersonic molecular beams (SuMBE) are presented. Compared to other vacuum deposition methods, it allows an accurate control on the initial state (kinetic energy, momentum, flux, etc.) of the molecules during the deposition process. We show that such feature can be efficiently exploited to prepare films, the structure and morphology of which resemble those single crystals, therefore achieving unprecedented control on their optical and electronic properties even for relatively thick samples (> 500 nm). We also report on the use of SuMBE for processes of co-deposition with the aim of functionalzing or doping organic semiconductors. We achieved co-depositions of a p-type semiconductor, as metal phthalocyanines, with a n-type semiconductor, as fullerenes, without phase segregation between the two compounds and with an high control on the deposition parameters. This aspect is very attractive for the growth of organic p-n junction in view of improving photovoltaic cells and gas sensors.