Indium oxide nanorods and nanowires on porous anodic alumina

We report indium oxide nanorods and nanowires with controllable microstructure deposited on porous anodic alumina membranes (PAAs). At the beginning of the deposition, indium oxide tends to nucleate on the top of PAAs, not at the bottom of PAAs' nanopores, and grows into nanorods. It is interesting that the indium oxide nanorods on the top of PAA just copy the topography of PAA, and form a new porous layer with the thickness of 40-50 nm. As the deposition goes on, the nanorods cannot maintain the ordered nanopore structure, and evolve into nanowire net. And the nanowires can stand upwards separately, and then fall down as the length goes up, forming an indium oxide entangled nanowires. The structure evolvement is discussed according to the field emission scanning electric microscope images.