Fabrication of highly-oriented nanoporous oxides: fundamentals of self-organization of nanopores induced by strong anisotropic crystal structures

作者发现，通过非晶Ta_2O_5和Nb_2O_5的晶化，纳米孔的自取向形成。该现象可应用于新型电子器件和过渡金属氧化物催化材料的制备。在本项目中，主要通过透射电子显微镜研究了取向纳米孔的形成机制。正交晶系的Ta 2 O 5和Nb 2 O 5具有强的各向同性晶胞; B轴比a和B轴长得多。结果发现，纳米孔生长垂直于两种氧化物的纵向B轴。此外，当晶粒在b轴方向上具有各种周期性时，观察到纳米孔的伸长得以实现。作者认为，强各向异性结构晶体生长中的结构柔性对纳米孔的单向生长起着重要作用。

The self-oriented formation of nanopores through the crystallization of amorphous Ta2O5 and Nb2O5 was found by the author. The phenomenon can be applicable to the preparation of new types of electronic devices and catalytic materials of transition-metal oxides. In the present project, the formation mechanisms of oriented nanopores were investigated mainly by transmission electron microscopy. Orthorhombic Ta2O5 and Nb2O5 have strong isotropic unit cells; the b axis is much longer than the a and b axes. It was found that the nanopores grow perpendicularly to the longitudinal b axis of both oxides. Furthermore, the elongation of nanopores was observed to be realized when the crystalline grains possess a variety of the periodicity in the b-axis direction. The author suggests the structural flexibility in the crystal growth of strong anisotropic structures plays an important role on the unidirectional growth of nanopores.