Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada.
Langmuir. 2013 May 28;29(21):6302-7. doi: 10.1021/la304944k. Epub 2013 May 16.
The epitaxial growth of organic molecules can lead to the formation of complex orientated morphologies. In previous work, we studied the kinetic and thermodynamic factors that drive the epitaxial growth of n-alkane thin films on HOPG(0001) and NaCl(001) by physical vapor deposition. A wide variety of morphologies are observed as a function of deposition conditions (substrate temperature, n-alkane chain length, etc.). In the current study we examine how a modified substrate (Au deposited on a HOPG(0001) or NaCl(001) substrate) affects the epitaxial growth of n-C36H74 (50 nm thick) relative to the uncoated substrates. This "indirect epitaxy", in which the patterned attractive forces of the substrate are transferred through a thin metal film, can tailor the conditions for epitaxial growth. The observation of fourfold symmetry for n-alkane growth on Au/NaCl(001) and sixfold symmetry for n-alkane growth on Au/HOPG(0001) demonstrates indirect epitaxy over a wide range of substrate temperatures during deposition.
有机分子的外延生长可以导致复杂取向形态的形成。在之前的工作中，我们通过物理气相沉积研究了 n-烷烃薄膜在 HOPG(0001)和 NaCl(001)上外延生长的动力学和热力学因素。作为沉积条件的函数（衬底温度、n-烷烃链长等），观察到了各种各样的形态。在当前的研究中，我们研究了经过修饰的衬底（在 HOPG(0001)或 NaCl(001)衬底上沉积的 Au）如何影响 n-C36H74（50nm 厚）相对于未涂层衬底的外延生长。这种“间接外延”通过薄金属膜传递衬底的有吸引力的图案化力，可以调整外延生长的条件。在沉积过程中，观察到 n-烷烃在 Au/NaCl(001)上的四对称性生长和 n-烷烃在 Au/HOPG(0001)上的六对称性生长，证明了在很宽的衬底温度范围内存在间接外延。
