准自由支撑铝薄膜中有序表面结构的自组织生长

利用真空热蒸发方法在液体基底表面成功制备出具有自由支撑边界条件的金属铝薄膜系统，研究了薄膜中自发形成的自边界向内部区域逐渐生长而呈带状分布的有序表面结构.该有序结构的形成与薄膜厚度、沉积速率和真空环境中的生长时间等实验参数密切相关，其形成过程可用一个三阶段生长模型来描述.实验证明此类有序结构是在薄膜内应力作用下，铝原子及原子团簇在液体表面自由扩散凝聚所致.进一步的理论研究表明：基于特征的边界条件和固液相互作用，该自由支撑铝薄膜系统中包含了丰富的正弦形内应力分布，各种具有不同振幅和频率的正弦形内应力的合成可形成矩形状畴块和带状有序结构. 关键词： 液体基底 铝薄膜 自组织生长 有序结构

Self-organization of ordered surface patterns in nearly free sustained Al films

A nearly free sustained aluminum film system has been successfully fabricated o n liquid substrates by thermal evaporation method. The ordered surface pattern s with band-shaped structure, propagating from the film edges to the central reg ions, are systematically studied. The formation of these patterns is strongly d ependent on the experimental conditions (such as the nominal film thickness, de position rate, growth period in vacuum etc.) and the growth mechanism can be tra ced to a three-stage process. The experiment proves that the ordered patterns re sult from the free diffusion and aggregation of the Al atoms and atomic clusters on the liquid surfaces driven by the internal stress. Further theoretical analy sis shows that due to the characteristic boundary condition and interactions bet ween the metallic films and the liquid substrates, the nearly free sustained Al films may contain a series of sinusoidal stress distributions with different amp litudes and frequencies, and their composition results in the formation of the o rdered surface patterns.