The fabrication of ordered semiconductor nanostructures has attracted increasing interest due to its applicability to various functional devices.  Among them, the semiconductor nanorods array is one of typical nanostructures available for the functional optical devices including solar cells, and display devices due to its unique physical properties originated from the geometrical structures.  Although various fabrication processes for the nanorod arrays have been reported, the efficient fabrication process of the ordered semiconductor nanorods array has not been established so far [1].  In the present report, the formation of the highly ordered semiconductor (ZnO) nanorods array based on anodic porous alumina templates will be presented.  The anodic porous alumina, which is formed by anodization of Al in acidic electrolyte, is one of typical self-ordered material with highly ordered hole arrangement [2].  The advantage of this material is its high controllability of the geometrical structures based on the anodizing conditions.  Especially, under the appropriate low voltage anodization condition, the highly ordered hole array structures with small hole interval and hole size can be obtained [3].  The hole interval and hole size in this highly ordered porous alumina were typically 25 nm and 10 nm, respectively.  In the present work, ZnO nanorods arrays were fabricated through the hydrothermal reaction [4] using the anodic porous alumina as a template for the synthesis.  Based on the present process, the highly ordered arrays of ZnO nanorods could be fabricated on the substrates.  The geometrical structures of the ZnO nanorods arrays were controlled by changing the structures of the porous alumina templates.  The obtained nanostructures will be applied to the fabrication of various kinds of energy conversion devices, which require the highly ordered nanostructures of semiconductors.

 1. W. I. Park, D. H. Kim, S.-W. Jung, G.-C. Yi, Appl. Phys. Lett., 80, 4232 (2002).

 2. H. Masuda and K. Fukuda, Science, 268, 1466 (1995).

 3. H. Masuda, K. Takenaka, T. Ishii, K. Nishio, Jpn. J. Appl. Phys., 45, L1165 (2006).

 4. T. Shinagawa, S. Watase, M. Izaki, Cryst. Growth Des., 11, 5533 (2011).