In situ X-ray characterization of oligophenylene thin films prepared by organic molecular beam deposition

In order to examine organic thin films during the deposition, we newly developed in situ observation system of an energy dispersive total reflection X-ray diffraction TRXD.equipped with an organic molecular beam deposition OMBD.. p-Sexiphenyl 6P., which is one of oligophenylenes, is noted as a useful material with unique optical properties by controlling the molecular orientation. To establish the method to control the molecular orientation in 6P thin films prepared by OMBD, 6P thin films on different substrates of silicon oxide SiO2.and uniaxially oriented poly p-phenylene. PPP. were examined by using in situ TRXD. In the case of the 6P thin films prepared on SiO2, 6P molecules formed with the normal orientation from the initial process of the deposition. On the other hand, it was observed 6P molecules on the oriented PPP substrates formed with the parallel orientation along the PPP chains. By using out of plane measurements, it was revealed that the 203.planes of 6P crystallites preferentially oriented parallel to the substrate surface. q1998 Elsevier Science B.V. All rights reserved.