1. A method of fabricating a semiconductor device, comprising: forming a first nanowire, the first nanowire being epitaxially grown in a longitudinal direction substantially perpendicular to a substrate; oxidizing the first nanowire to form a first nanostructure including a first insulator and a second nanowire; and oxidizing the second nanowire to form a second nanostructure including a second insulator and nanodots, wherein the nanodots are spaced substantially equally along a central longitudinal axis of the second nanostructure substantially perpendicular to the substrate.