US patent 7736741 - SWCNT Schottky junction

http://www.freepatentsonline.com/7736741.html

It is well known that single walled carbon nanotubes can be formed with either metallic or semiconductor characteristics based on the chirality of the nanotube. This patent from Sony Corp. teaches how to form a nanotube that integrates both the metallic and the semiconducting portions in a single nanotube which can provide basic rectifier functions on a molecular level and may simplify integration with electrode contacts. Claim 3 reads:

3. A method of manufacturing a single-wall carbon nanotube heterojunction comprising joining a semiconductive single-wall carbon nanotube and a metallic single-wall carbon nanotube via a growth defect with each other in a longitudinal direction thereof, wherein the defect introduced during growth of the single-wall carbon nanotube introduces a five-membered ring or a seven-membered ring into a six-membered ring structure of a graphene sheet thereby to induce a chirality change.