US Patent 7381983 - N-type carbon nanotube field effect transistor

http://www.freepatentsonline.com/7381983.html

In order to create CMOS structures in electronics both p-type and n-type transistors are required. For carbon nanotube transistors n-type doping have been difficult to construct. This patent from Samsung teaches a carbon nanotube field effect transistor in which the carbon nanotube semiconductor junction is n-doped via the inclusion of an electron donor material such as bismuth titanium silicon oxide to contribute a type V material (e.g. bismuth) to achieve an n-type transistor.

1. An n-type carbon nanotube field effect transistor (CNT FET) comprising:

a substrate;

electrodes formed on the substrate and separated from each other;

a CNT formed on the substrate and electrically connected to the electrodes;

a gate oxide layer formed on the CNT; and

a gate electrode formed on the gate oxide layer, wherein the gate oxide layer contains electron donor atoms which donate electrons to the CNT such that the CNT is n-doped by the electron donor atoms.