Unipolar nanotube and field effect transistor having the same

Abstract

Example embodiments relate to a unipolar carbon nanotube having a carrier-trapping material and a unipolar field effect transistor having the unipolar carbon nanotube. The carrier-trapping material, which is sealed in the carbon nanotube, may readily transform an ambipolar characteristic of the carbon nanotube into a unipolar characteristic by doping the carbon nanotube. Also, p-type and n-type carbon nanotubes and field effect transistors may be realized according to the carrier-trapping material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. FIGS. 1-5 represent non-limiting, example embodiments as described herein.

FIG. 1 is a diagram illustrating a cross-sectional view of a unipolar carbon nanotube field effect transistor (CNT FET) according to example embodiments;

FIG. 2 is a diagram illustrating bromine (Br) molecules sealed in carbon nanotubes (CNTs) according to example embodiments;

FIG. 3 is a graph of formation energy as a function of chirality of a CNT calculated using an Ab initio program when Br molecules and a CNT are combined according to example embodiments;

FIG. 4 is a graph of simulated partial density of state (PDOS) of a CNT as a function of energy using an Ab initio program when Br molecules are combined with the CNT according to example embodiments; and

FIG. 5 is a diagram illustrating a cross-sectional view of a unipolar CNT FET according to example embodiments.

Claims

1. A unipolar carbon nanotube, comprising: a carbon nanotube; anda carrier-trapping material sealed in the carbon nanotube,wherein the carrier-trapping material dopes the carbon nanotube.

2. The unipolar carbon nanotube of claim 1, wherein the carrier-trapping material includes halogen molecules, and the carbon nanotube is a p-type carbon nanotube.

3. The unipolar carbon nanotube of claim 2, wherein the halogen molecules are bromine (Br) or iodine (I) molecules.

4. The unipolar carbon nanotube of claim 2, wherein the halogen molecules are each formed of an odd number of halogen atoms.

5. The unipolar carbon nanotube of claim 1, wherein the carrier-trapping material is formed of electron donor molecules, and the carbon nanotube is an n-type carbon nanotube.

6. The unipolar carbon nanotube of claim 5, wherein the electron donor molecules include alkali metal molecules or alkaline-earth metal molecules.

7. The unipolar carbon nanotube of claim 6, wherein the alkali metal molecules are formed of cesium (Cs) molecules.

8. The unipolar carbon nanotube of claim 6, wherein the alkaline-earth metal molecules are formed of barium (Ba) molecules.

9. The unipolar carbon nanotube of claim 1, wherein the carbon nanotube is a single-walled carbon nanotube.

10. A unipolar field effect transistor, comprising: a source electrode and a drain electrode;a gate electrode;a first insulating layer that separates the gate electrode from the source and drain electrodes; andthe carbon nanotube and the carrier-trapping material according to claim 1, wherein the carbon nanotube electrically contacts the source and drain electrodes and functions as a channel region of the unipolar field effect transistor, and the carrier-trapping material is sealed in the carbon nanotube.

11. The field effect transistor of claim 10, wherein the carrier-trapping material includes halogen molecules, and the field effect transistor is a p-type field effect transistor.

12. The field effect transistor of claim 11, wherein the halogen molecules are bromine (Br) or iodine (I) molecules.

13. The field effect transistor of claim 11, wherein the halogen molecules are each formed of an odd number of halogen atoms.

14. The field effect transistor of claim 10, wherein the carrier-trapping material includes electron donor molecules, and the field effect transistor is an n-type field effect transistor.

15. The field effect transistor of claim 14, wherein the electron donor molecules are alkali metal molecules or alkaline-earth metal molecules.

16. The field effect transistor of claim 15, wherein the alkali metal molecules include cesium (Cs) molecules.

17. The field effect transistor of claim 15, wherein the alkaline-earth metal molecules include barium (Ba) molecules.

18. The field effect transistor of claim 10, further comprising a substrate, and a second insulating layer formed on the substrate, the source and drain electrodes and the carbon nanotube are positioned on the second insulating layer, and the carbon nanotube extends between the source and drain electrodes.

19. The field effect transistor of claim 18, wherein the substrate is doped and functions as a back gate.

20. The field effect transistor of claim 10, wherein the second insulating layer is positioned on the carbon nanotube, and the gate electrode is positioned on the second insulating layer.

21. The field effect transistor of claim 10, wherein the carbon nanotube is a single-walled carbon nanotube.