Synthesis and Characterization of Nonlinear Nanopores in Alumina Films
journal contributionposted on 17.04.2007, 00:00 by Rashid Zakeri, Clay Watts, Haibo Wang, Punit Kohli
Controlled and convenient synthetic approaches for more complex-shaped nanotubes and nanowires of different materials are needed to further advance the field of nanoscience and nanotechnology. In this paper, we report the synthesis and characterization of nonlinear nanopores (such as curved and dendritic nanopores) containing alumina films. We show that control over the orientation of nanopores can be accomplished by controlling the geometric shape of aluminum substrates on which nanoporous alumina is grown. The anodically grown alumina on square and rectangular aluminum substrates showed cracks at the sharp edges of the substrates but no cracks were observed in nanoporous alumina films grown on cylindrical substrates. Our electrostatic calculations suggest that the electric field intensity at sharp edges of the rectangular/square substrates is significantly larger than that at the flat faces of the substrates. This leads to a faster alumina growth rate and hence increased stresses at these edges. We also propose a simple model that predicts the shape and orientation of nonlinear nanopores grown on different geometric shaped substrates. Through the use of proposed nanoporous films as template, one can easily synthesize highly complex-shaped nanotubes and nanowires of different materials.