Coaxial p- and n-type carbon nanotube transistors with dopant-selective   coatings
  Carbon nanotube field-effect transistors (FETs) with passivated coaxial gate structures have been fabricated after growth of contacted suspended single wall nanotubes (SWNTs) and subsequent coating with gate dielectrics. Electron Fabry-Perot interferences are observed in the FETs indicating ballistic transport in the coated structures. Reliable production of high-performance SWNT FETs has been obtained by combining patterned growth of SWNT arrays with feed-back controlled electrical breakdown to select desired semiconducting SWNTs, making large-scale SWNT FET fabrication achievable. P-type and n-type passivated SWNT FETs have been realized through dopant-selective nanotube coatings, which enables the fabrication of active circuits based on complementary device structures. 
Haibing Peng and Jene A. Golovchenko