variance less than about 20 e g less than about 10 less than about 5 or less than about 1 over the region of greatest variability and over a linear dimension of at least 5 nm e g at least 10 nm at least 20 nm or at least 50 nm typically the diameter is evaluated away from the ends of the nanowire e g over the central 20 40 50 or 80 of the nanowire a nanowire can be straight or can be e g curved or bent over the entire length of its long axis or a portion thereof in certain embodiments a nanowire or a portion thereof can exhibit two or three dimensional quantum confinement nanowires according to this invention can expressly exclude carbon nanotubes and in certain embodiments exclude u201c whiskers u201d or u201c nanowhiskers u201d particularly whiskers having a diameter greater than 100 nm or greater than about 200 nm examples of such nanowires include semiconductor nanowires as described in published international patent application nos wo 02 17362 wo 02 48701 and wo 01 03208 carbon nanotubes and other elongated conductive or semiconductive structures of like dimensions which are incorporated herein by reference as used herein the term u201c nanorod u201d generally refers to any elongated conductive or semiconductive material or other material described herein similar to a nanowire but having an aspect ratio length width less than that of a nanowire note that two or more nanorods can be coupled together along.