Carbon nanotubes (CNTs) have been intensively studied as an ideal material for building complementary metal-oxide-semiconductor (CMOS) logic circuits and nano-electro-mechanical systems (NEMS), due to their unique mechanical and electrical properties such as high Young's modulus, high current carrying capability, etc. Many CNT devices have been developed, such as: SWCNT field-effect transistor (FET) based logic gates, SWCNT memories. CNTs, especially suspended nanotubes, have many advantages in chemical, optical or displacement sensing applications as well as resonant NEMS devices. Meanwhile, their ultra-small dimension makes them the excellent candidate for future scaling down.