Available Technology
Coating suspended nanotubes with silicon nitride
Technology:
Carbon nanotubes
Markets Addressed
Since their discovery over a decade ago, carbon nanotubes have been the subject of intense study because of their unique electrical, thermal, and mechanical properties. They have been proposed as the basis of new sensors, nanoscale electrical circuits, molecular delivery systems, photonic sources, thermal conductors, mechanical fibers, chemical catalysts, and as critical components for a wide variety of other applications.
Micro- and nano-electronics based on semiconductor carbon nanotubes (CNTs) require methods of controlling their properties and of preserving those properties once gained. The inventors have shown for the first time that both p-type and n-type CNTs (semiconducting) can be predictably and repeatebly produced and preserved by coating CNTs with selected materials. It has been further demonstrated that efficient and reliable dielectric coating of CNTs can be performed by vapor deposition techniques.
Applications include micro- and nano-electronics.
Innovations and Advantages
FETs were made by combining the techniques of Harvard Case 2093 to produce CNTs extending over a trench between two electrodes with the coating techniques of the present invention and conventional photolithographic techniques.
The invention is a method for the coating of suspended nanotubes with silicon nitride (Si3N4) using low-pressure chemical vapor deposition (CVD). This issued patent includes the fundamental design of suspended carbon nanotube transistors. The main claim of this patent is:
A carbon nanotube field effect transistor comprising: a carbon nanotube having a length suspended between a source electrode and a drain electrode that are together disposed on a common surface of a support structure; a gate dielectric material coaxially coating the suspended nanotube length and coating at least a portion of the source and drain electrodes; and a gate metal layer coaxially coating the gate dielectric material along the suspended nanotube length and overlapping a portion of the source and drain electrodes, separated from the electrodes by the gate dielectric material.
The nitride passivation of the nanotube increases their stability and robustness and allows for precise tailoring of the sensitivity to environmental ambients. A three-terminal field-effect transistor has been produced by coaxially coating the nanotube with a nitride and a metal layer, allowing nanotubes to be used as both active and passive sensor elements.
Additional Information
Intellectual Property Status: The invention is not available for licensing in all fields. A US provisional patent application was filed June 8, 2004. US Patent issued: #7,253,434
Publications:
-“Coulomb blockade in suspended Si3N4-coated single-walled carbon nanotubes”, H.B. Peng, and Jene A. Golovchenko, Applied Physics Letters, 84, 5428-5430 (2004).
-For more information see Applied Physics Letters 84(26) 5428-5430 (2004).
A suite of four technologies (Harvard cases 2784, 2616, 2281, and 2093) has been developed by Roy Gordon, Charles Lieber, and Jene Golovchenko at Harvard University involving carbon nanotubes. The researchers have developed a number of novel techniques for the synthesis, controlled growth and placement on substrates of high-quality single-walled carbon nanotubes particularly suited for sensor applications.
This IP enables carbon nanotubes to be used for extremely sensitive gas and chemical detection, taking advantage of their extremely high electron mobility, small dimensions, and reduced power consumption.
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Inventor(s):
Golovchenko, Jene
Peng, Haibing
Categories:
For further information, please contact:
Alan Gordon, Director of Business Development
(617) 384-5000
Reference Harvard Case #2281