Controlled fabrication of hierarchically branched nanopores, nanotubes, and nanowires

An ordered nanopore array, comprising:

• a template material and two or more levels of ordered nanopores;
• a first level of nanopores comprises stem nanopores;
• a second level of nanopores comprise branch nanopores, such that at least two branch nanopores in the second level of nanopores are connected to each stem nanopore in the first level of nanopores;
• and
• further comprising at least one of:
• (a) a third level of nanopores comprising branch nanopores, such that at least two branch nanopores in the third level of nanopores are connected to each branch nanopore in the second level of nanopores;
• or
• (b) at least three branch nanopores in the second level of nanopores are connected to each stem nanopore in the first level of nanopores.

A method of making a nanopore array, comprising:

• anodically oxidizing a template material at a first voltage to form a first level of stem nanopores in the template material;
• anodically oxidizing the template material at a second voltage lower than the first voltage to form a second level of branch nanopores connected to the first level of stem nanopores;
• and
• anodically oxidizing the template material at third voltage lower than the second voltage to form a third level of branch nanopores connected to the second level of branch nanopores.

A method of making a nanopore array, comprising:

• anodically oxidizing a template material at a first voltage to form a first level of stem nanopores in the template material;
• and
• anodically oxidizing the template material at a second voltage lower than the first voltage to form a second level of branch nanopores connected to the first level of stem nanopores;
• wherein the second voltage is less than the first voltage by a factor of 1/√{square root over (n)}, where n>2, to form n second level branch nanopores connected to each first level stem nanopore.