SEM/TEM characterization of periodical novel amorphous/nano-crystalline micro-composites obtained by laser interference structuring: The system HAlO-Al-Al2O3

Layers of the metastable, amorphous HAIO are synthesized by chemical vapor deposilion from he molecular compound tert-buloxyalane ([tBu-O-AlH2]2). At temperatures above 500 °C, these layers transform to biphasic Al center dot AlO3due to the elimination of di-hydrogen. The interaction of HAIO films with short laser pulses causes partial transformation of amorphous HAIO into nano-crystalline Al∙Al2O3. Using an interference pattern of two coherent high-power Nd:YAG laser beams produces local and periodic heating, inducing crystallization at equally distant lines in the HAlO layer. Depending on the laser fluence, different morphologies and different amounts of crystalline phases are obtained. In this study, the surface morphology and the distribution of crystalline phases of the structured samples are analyzed using SEM, FIB and TEM. The two-dimensional structures consist of periodic variations of morphology, chemical composition, and phase identity with a well-defined long-range order. When bio-functionalized, the structured samples may be used as carriers for structurally controlled cell-cultivation.