STUDY OF ORGANIC THIN FILM GROWTH BY MODULATED MOLECULAR BEAM SCATTERING AND SEARCH FOR CATALITIC CONTROL FACTOR

有机大分子的分子束散射技术已发展并用于有机薄膜生长的研究。本研究主要针对以下三个方面：（1）有机分子与无机表面之间的货车范德华相互作用的精确测量。(ii)脉冲分子束控制有机薄膜生长动力学。(iii)寻找能控制生长动力学的催化吸附质。取得了以下结果。(i)用氢酞菁和C_（60）的脉冲分子束辐照各种无机材料，得到了它们的表面停留时间。对基底材料的依赖顺序为离子型>金属型>非晶型，这表明分子与基底之间的相互作用强度。在非晶衬底上的表面停留时间小的原因可能与“量子摩擦”有关，在“量子摩擦”中，分子与表面之间的电荷分布的简化是重要的。(ii)脉冲分子束用于有机薄膜的生长。结果表明，在薄膜生长的第一阶段的成核动力学可以通过改变脉冲的宽度来控制。当分子具有强各向异性时，即使占空比相同，成核密度也可以作为脉冲持续时间的函数取最小值。从理论上分析，这一发现可以解释为碰撞诱导解吸的迁移分子。(iii)在碱金属卤化物上实现了Alq3的外延生长。通过高能电子衍射的精确分析，发现该异构体是“mer”。该分子可以作为有机薄膜生长的催化控制因子的候选者。

Molecular beam scattering technique for large organic molecules has been developed and used for the study of organic thin film growth. The study aimed at three subject : (i) Precise measurement of van der Waals interaction between organic molecules and inorganic surfaces. (ii) Controlling the kinetics of organic thin film growth by pulsed molecular beams. (iii) Search for catalytic adsorbate which can control the growth kinetics. The following results have been obtained.(i) Pulsed molecular beams of hydrogen phthalocyanine and C60 were irradiated on various ingoranic materials and surface residence time was obtained. The substrate materials dependence is in the order of ionic>metal>amorphous, which suggests the strength of the interaction between the molecules and the substrates. The reason why the surface residence time is small on the amorphous substrates might be related with the "quantum friction" in which the commensuration of charge distribution between the molecules and the surface is important.(ii) Pulsed molecular beams were used for organic thin film growth. It was found that the nucleation kinetics at the first stage of the thin film growth can be controlled by changing the width of the pulses. When the molecules have strong anisotropy, the nucleation density can take a minimum as a function of the pulse duration even if the duty ratio is the same. From the theoretical analysis, this finding can be explained by collision induced desorption of the migrating molecules.(iii) Epiaxial growth of Alq3 was achieved on alkali halide. The isomer has been found to be "mer" by precise analysis of high energy electron diffraction. This molecule can be a candidate for the catalitic control factor for the organic thin film growth.